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More Details? CHECK-OFF Page 94 march 1974 1 DRAKE TR-72WWW.RADiOSCAMATORUL.Hi2.RO Transceiver

WWW.GiURUMELE.Hi2.RO

GENERAL: Frequency coverage: 144-148 MHz 23 channels, 2 supplied (.52/.52 and .34/.94) Completely solid state Current 23 Channels drain: Rcv 0.4 A. Xmit 2.7 A (Hi power) or 1.2 A (Lo power) Voltage required: 13.8 VDC Antenna impedance: 50 ohms Frequency Superior adjusting trimmers on every crystal Size: Selectivity ~J,,'~Wx 2I,"H x 9XCD (18 x 6 x 24 c~) Weight: 512 Ibs. (2.5 kg). TRANSMITTER: RF output power: 10 W min. Completely (Hi power) or 1 w (LO power) at 13.8 VDC Frequency deviation: adjustable to 215 kHz Solid State max., factory set to f6.5 kHz Automatic VSWR protection RECEIVER: Crystal-controlled, double con- version superhet Sensitivity: Less than .35,~V for 20 dB quieting Selectivity: 20 kHz at -6 dB (230 kHz and adjacent channel rejection at least 80 dB down) Audio output: 1 W Audio output impedance: 8 ohms Modulation ac- Including dynamic microphone, ceptance: 27 kHz Image rejection: -65 dB DC power cord, mobile mount and desk mount brackets, microphone Intermodulation and other spurious responses: hanger, auxiliary connector, and at least 70 dB down. external speaker plug AC-10 POWER SUPPLY -- for 115 VAC operation Q $39.95 For complete details contacc 540 Richard St., Miamisburg, Ohio 45342 Rm Lm DRAKE COMPANY Phone: (5.13, 866-2421 Telex: 288-017

2 march 1974 More Details? CHECK-OFF Page 94 March, 1974 volume 7, number 3

staff James R. F~sk.W1 DTY editor-~n-ch~ef

Joseph Schroeder, W9JUV editor

WWW.RADiOSCAMATORUL.Hi2.ROPatricia A. Hawes, WNlQJN asslstant editor

J.Jay O'Brien, W6GDO fm editor

Alfred Wilson, W6NIF James A. Harvey, WAGIAK associate editors Wayne T. Pierce, K3SUK contents cover

T H. Tenney. Jr WlNLB publisher

WWW.GiURUMELE.Hi2.ROHilda M. Wetherbee 6 ssb and CW transceiver assistant publisher W. J. Weiser, M. D., VEBGSD advert~slngmanager

22 open repeater access system offices R. B. Shreve. W8GRG Greenv~lle,New Hampshire 03048 Telephone: 603-878-1441

ham radio magazine IS oublished monthlv. bv . 26 six-meter Corrtmmlcatoons Technology. Inc Kenneth W. Robbins, WIKNI Greenv~~le.Nem tiampsh~re03048

Subscription rates, world w~de one year. $7.00, three years, $14.00 Second class postage 34 vertical antenna characteristics paid at Greenv~lle.N.H. 03048 and at additional ma~lingoffices Robert E. Leo, W7LR

Foreign subscription agents Un~tedKingdom Radio Society of Great Br~taln 35 Doughty Street, London WCl. England 38 lowpass filters for solid-state linears G. Kent Shubert, WA0JY K All European countries Eskil Persson. SMSCJP, Frotunagrand 1 19400 Upplands Vasby. Sweden

Afr~cancontinent 42 simplified digital readout system Holland Radio, 143 Greenway Greenside. Johannesburg Harold W. Thompson, W601S Republ~cof South Afr~ca

Copyr~ght1974 by Communications Technology, I nc 50 how to bias fets Tttle reg~steredat U.S. Patent Office Pr~ntedby Wellesley Press, Inc Courtney Hall, WA5SNZ Fram~ngharn,Massachusetts 01701. USA

ham rad~oIS ava~lableto the bl~nd and phys~callyhandicapped on magnetlc tape from Sctence for the Bltnd 221 Rock H~llRoad Bala Cynwyd 4 a second look 56 ham notebook Pennsy lvan~a19440 Mtcrof~lmcoples of current 94 advertisers index 58 new products and back Issues are ava~lable 54 comments 94 reader service from Unlvers~tyM~crof~lms Ann Arbor. M~ch~gan48103 83 flea market 64 short circuits

march 1974 3 jm look fisk

A few months ago, down in Oklahoma, the background to differentiate between several old-time radio amateurs, each now the valuable antique and the valueless retired, attendedWWW.RADiOSCAMATORUL.Hi2.RO an auction of the elec- junk is frighteningly small. Antiques that tronics equipment and junk collection of can never be replaced, items not pre- a prominent local amateur. From all served in any collection, are going to be reports, it was quite a collection, filling bulldozed under at a county landfill four large warehouses. Except for the dump, and that's a bloody shame. huge volume (and original cost) the col- This scene, on a much more modest lection resembled the typical "hell box" scale, is probably repeated many times a of every amateur who lived through the year. Without getting morbid, each one of halcyon days when building your own us should realize that we are not immor- transmitter was conventional practice and tal. Each of us has a collection of everyoneWWW.GiURUMELE.Hi2.RO eagerly added to his junk collec- electronic gear that we've acquired over tion at every possible opportunity. The the years that will, if someone doesn't same is still true to a somewhat lesser know any better, be bulldozed under extent, with amateurs maintaining large with the trash at the city dump when we collections of old and new electronic join the list of Silent Keys. Each item, goodies for some, yet unplanned, project. when you acquired it, represented a jewel Talk to any amateur who has been to be treasured and was carefully put around for a few years and you're sure to away. If you were ever so careless as to find a garage, an attic or a basement full! toss out one of these treasures, you could However, there was one big difference be sure you would have an almost im- in the Oklahoma collection. Where most mediate pressing need for an identical radio amateurs painfully part with dol- article. I know, because it's happened to lars, this amateur had painlessly parted me everytime I've cleaned house! with thousands of dollars. The contents The point is this: Talk to your heirs. of the four warehouses vividly reflected Clue them in as to what items belong in a this difference. Think back a few years - museum. Better yet, make arrangements what was the most delectable piece of with the executor of your estate to radio gear you could imagine? It was donate certain prized items to the muse- probably in the Oklahoma collection. um of your choice. This applies not only And not just one, but several. Parts, radio to equipment, but to your library of old sets, test equipment, you name it, it was books. The same sort of fore- all there in unimaginable profusion. One sight applies to your newer equipment as whole warehouse floor was crammed full well. Give your executor the names of of big transmitters, spark coils and rotary several trusted amateur friends who will gaps for 1920-style transmitters, spider- help dispose of modern radio gear and web coils and thousands of variable test equipment. They will know the fair of every possible make and market value - the executor may not. description. The list could go on for There have been more than a few cases pages. where an amateur's survivors have been Now here's the tragedy: These price- ripped off to the tune of thousands of less articles, which belong in a museum, dollars. Don't let it happen to your were grouped in huge lots with utter junk family. and sold to the only people who can handle large lots of junk - junk dealers! Jim Fisk, WIDTY The probability that these dealers have editor-in-chief WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

r EAR CLL and

' A WORLD TRAVELER

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ON COMPA; MHnnc I ING DEPT. (. P 0. BOX 1542 GOLETA. CALlFORNlA 93017 AREA COC)E 805 967-5511 simple ssb transmitter and receiver WWW.RADiOSCAMATORUL.Hi2.RO for 40 meters sidered for the two higher-frequency bands, 10 and 15 meters. the receiver A look at the block diagram in fig. 1 Complete construction shows that the basic receiver circuit is a rather conventional single-conversion information for a super-heterodyne. The incoming 7-MHz signal is coupled to the first rf , WWW.GiURUMELE.Hi2.ROQ1, amplified, and applied to gate 1 of no-frills ssb and CW the mixer, Q2 (fig. 2). The dual-gate used in the rf amplifier and mixer transceiver system stages provide high gain, low noise and a minimum of cross-modulation problems. that offers These particular devices are also internal- ly gate protected, a significant bonus when the receiver is used in strong rf high performance fields. CR1 and CR2 are included in the input circuit as additional protec- at low cost tion to the first rf stage. The 6.545- to 6.845-MHz vfo signal is injected at gate 2 of the mixer. The 455-kHz difference frequency is selected by the i-f , TI. The very This article describes a simple, high- stable vfo circuit features incremental performance 40-meter ssb and CW re- tuning and output buffering, and is a ceiver and transmitter. The receiver in- modification of an earlier design (fig. 3).1 corporates a very stable vfo and incre- Output buffering is provided by the mental tuning while the transmitter emitter-follower stages 06 and 07. Tran- features 180-watt PEP input. Although sistor Q7 also serves as a power amplifier, the receiver was designed to operate in allowing the vfo to drive a 7360 balanced conjunction with a companion 40-meter mixer tube used in the companion ex- exciter, it can also be used with any citer. number of separate exciters. The incremental tuning circuit uses a Furthermore, the basic design can be Motorola MV1654 varactor , CR3. used on any of the amateur bands from This circuit permits an approximately 80 through 10 meters by simply using the 10-kHz offset to either side of the vfo appropriate tuned circuits in the rf and frequency. The control voltage on the mixer stages, and by changing the fre- varactor is set by R3, the offset tuning quency of the vfo so it tunes 455 kHz control. R4 compensates for below the desired band. For maximum differences in varactors and allows the vfo stability vfo pre-mixing should be con- to be adjusted to zero offset.

6 march 1974 S2 allows the receive offset to described receiver (fig. 61.2 The use of a be activated manually; receiver offset is CA3028A as the product detector allows automatically turned off by K1 significant conversion gain in this stage. when the receiver is placed in the trans- The high-impedance output of the mit or standby mode. This particular type CA3028A is matched to the base of the of switching is necessary because a audio preamplifier , Q8, through 1.5-kHz frequency difference between transformer T5. Although the Motorola the transmitted and received signal exists MC1454 provides more than sufficient at my station. This frequency difference audio output, an MC1554 or HEP593 resulted from the use of a 455-kHz may be substituted for even more audio. mechanical filterWWW.RADiOSCAMATORUL.Hi2.RO in the exciter and a Alternately, a Motorola MFC9010 can be 453.5 kHz filter in the receiver. If you are used to replace both Q8 and U2 and building from scratch, I recommend that deliver about 2-watts of audio.3

MIXER WWW.GiURUMELE.Hi2.RO

TO XMTR TUNING

fig. 1. Block diagram of the single-conversion 40-meter receiver ssb and CW receiver. you use a 455-kHz filter in the receiver, In my receiver with the audio gain such as the Collins FA21-7102. control, R2, adjusted for maximum gain, The two-stage i-f amplifier, Q3 and the MC1454 was driven into oscillation Q4, is relatively straightforward and pro- by transistor Q8. This was corrected by vides more than enough i-f gain (fig. 4). bypassing a small amount of the input For the sake of simplicity I did not audio signal to ground through C7 (0.1 include an agc system in the receiver - if pF). Because of component differences, you want to include agc, it should be and differences in circuit layout, you may connected to gate 2 of the rf and i-f not require this bypass . amplifier stages, Q1, Q3 and 04. Any well-regulated power supply with An MPFl02 fet is used in a simple bfo an output of 12 to 13.5 volts may be circuit which is based on the old tuned- used with this receiver. Excellent voltage grid, tuned-plate vacuum-tube circuit (fig. 5). Bfo output is taken from the second- ary of transformer T4. For optimum performance of the CA3028A product detector, U1, the amplitude of the bfo injection voltage should be 2 to 3 volts rms. The sideband crystals are selected by switch S1. The crystal frequencies shown in the diagram are for use with a Collins 455-kHz . The product detector and audio stages Homebrew 40-meter receiver uses all solid-state used here were adapted from a recently circuits.

march 1974 7 regulation is required to ensure maximum The I-inch-deep aluminum chassis, vfo stability because the MV1654 varac- 10-inches long and 5%-inches deep, is tor used in the incremental tuning system installed in a commercial enclosure. The will significantly shift the vfo output rf amplifier and mixer tuning capacitor, frequency with the slightest dc voltage C1, is a modified dual-section 365-pF variation. For additional vfo stability it broadcast variable with all but two rotor might be a good idea to insert a three- plates removed from each section. With terminal IC, such as the the values given for C8 and C9, the Fairchild pA7812, in the vfo supply modified variable will cover the frequen- line.4 cy range from 7.0 to 7.3 MHz. receiver constructionWWW.RADiOSCAMATORUL.Hi2.RO receiver alignment The mechanical layout of the receiver Before starting the alignment pro- is shown in the photographs. The rf cedure, all slug-tuned coils must be rough-

WWW.GiURUMELE.Hi2.RO

VFO +12V (FIG. 3)

C1 modified dual-section 365-pF Ll,L3 30 turns no. 26 wound on 114" broad-cast variable (see text) slug-tuned ceramic form, resona- FL1 455-kHz mechanical filter, ted to 7.15 MHz 2.1-k~zbandpass (Collins FA21- L2 4 turns no. 26 on cold end of ~1 7102) T 1 455-kHz input i-f transformer fig. 2. Schematic diagram of the rf amplifier, mixer and mechanical filter. amplifier, mixer and mechanical filter are ly adjusted to the proper frequencies with constructed on a 2%x2'/4-inch section of the help of a grid-dip meter. Also, each Vector board, copper clad on one side. stage is initially tested and aligned before The i-f amplifier is built on another, being mounted on the chassis. This points similar sized board, and the vfo and up any difficulties that might be more incremental tuning are built on another difficult to pinpoint when the receiver is 2%-inch square board. These three boards completely assembled. L4 in the are mounted on 314-inch spacers under vfo is adjusted for an output of 6.695 the chassis. MHz with C4 set at mid-excursion. The bfo, product detector, and audio Although a signal generator is best for stages are built on a 2%x5-inch board initial alignment of the rf and mixer which is mounted on top of the chassis stages, it is possible to use an on-the-air on 1-314-inch spacers. Relay K1 is in- signal. Apply a 7.15-MHz signal to L1 and stalled under this board. Each board is peak C1 for maximum rf voltage on gate built and tested individually, and con- 1 of the rf amplifier stage. Next apply a nected to the others with miniature 455-kHz signal to the primary of TI and shielded cable. tune the transformer for maximum signal

8 march 1974 at the output of the mechanical filter. the midpoint of this dc voltage swing. Since a reading of 0.1 volt is typical here, With the incremental tuning turned off, a sensitive rf probe and voltmeter is vfo output is centered at its mid-frequen- required. cy point with R4, and resistor R3 will To align the i-f amplifier a 455-kHz move the vfo about 10 kHz to either side signal is applied to gate 1 of transistor Q3 of this center point. and T2 and T3 are tuned for maximum signal at the output of T3. The receiver performance bfo should require no adjustment al- The performance of the receiver is though T4 may be tuned, as required, if most rewarding. It appears to be as the bfo fails to oscillate.WWW.RADiOSCAMATORUL.Hi2.RO sensitive as my FTDX-401, and its fre- After each of the individual boards has quency stability is excellent. No signifi- been tested and aligned, and the receiver cant vfo warmup drift has been noted, has been assembled, final peaking can be the audio is apparently distortion free,

Rear viewWWW.GiURUMELE.Hi2.RO of the 40. meter receiver. The pro- duct detector and audio board is mounted on 1-3/4" spacers. Relay K1 is underneath the board while the vfo tuning capacitor is on the right.

accomplished with an on-the-air signal. and the set provides more than enough The rf amplifier, mixer and i-f stages are gain. One very pleasing feature of the tuned for maximum receiver gain. To stages is their very low noise obtain good tracking with C1 it is neces- figure. The ambient noise level in this sary to alternately re-tune the mixer and receiver is the lowest of any comparable rf amplifier coils, L1 and L3, several receiver I have ever used. times. The vfo inductor, L4, is accurately adjusted and the tuning dial calibrated the transmitter with the aid of a communications receiver The 180-watt PEP ssb transmitter may equipped with a crystal calibrator. be used as a separate unit, or with the To align the incremental tuning sys- receiver. The unit is completely self- tem, monitor the received frequency, contained and incorporates a stable vfo, adjust resistor R3 and note the amount of power supply and all the necessary con- frequency change. A 40% change in the trol functions for antenna switching and resistance of R3 should result in an receiver muting. The use of an RCA 7360 approximate 20-kHz shift in the vfo beamdeflection tube for the balanced frequency. The dc voltage range coin- modulator and balanced mixer stages ciding with this frequency shift is mea- provides excellent carrier suppression and sured at the wiper of R3 and should be in local-oscillator rejection, two require- the range from zero to about 2.5 volts. ments that are difficult to achieve in When the dc voltage required for a single-conversion ssb exciters which use a 20-kHz frequency shift has been deter- 455-kHz i-f. mined, the wiper of resistor R4 is set to A block diagram of the transmitter is

march 1974 9 shown in fig. 8. The output of the grid 1 and grid 2) serves as a self-oscil- high-impedance microphone is amplified latory carrier generator, with switch by V101, and applied to one of the S101A selecting either Y 101, a 455-kHz deflection electrodes of V102, the 7360 crystal for tuneup or CW, or Y102, balanced modulator. The crystal-con- 456.25-kHz crystal for lower-sideband trolled carrier signal is injected at the operation. For tuneup or CW one of the (see fig. 9). The 455-kHz deflection plates of V102 is grounded by

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fig. 3. Vfo for the 40-meter receiver includes incremental tuning. XI-~3 Inductor L4 consists of 5 turns no. 22 wound on a H" slug-tuned ceramic form, well covered with coil dope. For maximum stability an IC voltage regulator may be added to the circuit (see text). double-sideband output signal is coupled switch S1O1 B, effectively unbalancing the into a Collins mechanical filter. modulator so that a 455-kHz carrier One of the absolute requirements of a signal appears across the output network. modern single-sideband exciter is ade- In ssb service the audio signal applied to quate carrier suppression. By using a one of the deflection plates unbalances 7360 beamdeflection tube up to 60-dB the modulator. of carrier suppression can be achieved if Another requirement for effective and careful construction and layout have been courteous single-sideband operation is followed, and the circuit has been proper- adequate suppression of the unwanted ly adjusted. sideband. The Collins mechanical filter The section of V120 (cathode, can provide up to 60dB of sideband attenuation if careful attention is given to mechanical layout, and stray coupling is prevented between the input and output of the filter. The filter also attenuates the 455-kHz carrier signal by an additional 20 dB. The 120-pF capacitor across the output of the filter helps match the output impedance of the filter to the input impedance of the 6BA6 i-f ampli- fier, V103 (see fig. 10). Top view of the receiver chassis. The vfo board is to the left, the product detector and audio The ssb signal from the output of the board to the right. 6BA6 i-f amplifier is coupled through

10 march 1974 transformer TI01 to V104, the 7360 short as possible and the input and balanced mixer. The triode section of output must be sufficiently isolated; the V104 is used in a Colpitts-type internal 33-ohm non-inductive resistor in series vfo. Capacitor C102 is the main tuning with the grid serves as a parasitic suppres- capacitor and C103 and C104 serve both sor. as frequency-trimming and temperature- The screen bypass capacitor is soldered compensating capacitors. For transceive directly across the base of the 6GK6

WWW.RADiOSCAMATORUL.Hi2.RO

F ROW :F$" 6

fig. 4. TWO-stage 455.kHz i-f amplifier. Transformers TZ and T3 are miniature 455-kHz input i-f transformers. WWW.GiURUMELE.Hi2.RO operation the internal vfo is bypassed and socket between the input and output pins an external vfo coupled into grid 1 and the ground end is also soldered to the through switch S102. central pin of the socket. This technique One problem when designing a 40- provides an effective grounded shield meter ssb exciter using a 6.545-MHz vfo between the input and output circuits of and a 455-kHz i-f in a single-conversion the driver stage. system is inadequate vfo suppression. The output of the 6GK6 driver is Since the vfo frequency is only separated coupled into the grids of V106 and V107, from the desired output frequency by the 61468 power-amplifier tubes through 455 kHz, a single-tuned resonant circuit C106 and L104. Capacitor C106 should in the output of a conventional mixer be pruned by removing plates from a stage would probably not be inadequate miniature until the to sufficiently attenuate the vfo signal." tuned circuit resonates from 7.0 to 7.3 However, by using a 7360 beam-deflec- MHz with one full revolution of the shaft. tion tube as a balanced mixer, up to Fix-tuning the power amplifier's grid cir- 40-dB of vfo rejection is possible. cuit to the desired band makes tuneup The 7.0- to 7.3-MHz ssb output from simple and prevents the operator from V104 is coupled through L102-L103 to inadvertently tuning the final amplifier to the 6GK6 driver stage, V105, fig. 11. A some unwanted spurious signal that may 6GK6 was selected as the driver because appear at the output of the high-gain it offers considerable gain and can safely handle a 300-volt plate supply. However, because of its high gain, care must be taken to prevent instability and self- oscillation. All leads must be kept as

"Both single- and double-tuned bandpass cir- cuits were tried by the author. The double- tuned bandpass arrangement was workable with a conventional 6BA7 mixer stage, but it al- lowed an unacceptably high level of vfo signal fig. 5. The 455-kHz bfo stage. T4 Is a mlniature to feedthrough to the driver stage. 455-kHz i-f input transformer.

march 1974 11 driver stage. Resistor R105, a 5000-ohm, the cathode keying line to prevent self- 5-watt wirewound , serves oscillation. Parasitic suppressors 2101 as the driver gain control. and 2102 help minimize any high-fre- A pair of 6146Bs in parallel are used as quency instability. With these techniques, a power amplifier (fig. 12). These tubes I did not find it necessary to neutralize are still among the best power amplifier either the driver or PA stages. Both are tubes for ssb service, offering good linear- extremely stable.

IY

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BFO +12V INPUT WWW.GiURUMELE.Hi2.RO(FIG 5)

fig. 6. Product detector, audio preamplifier and audio output stage. Capacitor C7 (0.1 pF) may be required to suppress an oscillating output stage (see text).

ity, excellent IMD characteristics and The final-amplifier tank circuit is a good power sensitivity. They can also standard pi network. Capacitor C108 is a withstand considerable abuse during grog- surplus, high-voltage 400-pF variable. gy-eyed, early morning DX chasing tune With the values specified for C107 and ups. L105, the stage loads nicely into a 50- As with the driver stage, considerable ohm resistive load. You may wish to care must be taken in keeping leads short change the value of L105. In that case an around the PA stage sockets, separating additional capacitance (C109, 100-400 input and output circuits, and shielding pF) may be needed in parallel with C108 to load properly. Or, if you wish, a TO -,. -ANTENNA triple-section 365-pF broadcast variable, ANTENNA lNPUT 0 CIRCUIT *f? Z, with all sections in parallel, may be I substituted for C108. NC GI OF at o In the interest of simplicity and thrifti- ness, a grid and plate current metering 'h +12V system was excluded in favor of a simple rf output indicator. A sample of the S3 RECEIVE OFF output rf is applied to a 1N34A diode through a voltage-dividing network; the POWER TRANSMIT rectified dc is filtered and read on a 0-1 milliameter. Resistor R106 serves as a sensitivity control. RECEl VE STANDBY transmitter control circuits u;:; Since this exciter was intended to fig. 7. Switching and control circuits for the work in conjunction with the matching 40-meter receiver. Relay KI is a miniature receiver, antenna switching and receiver 4-pole relay with a 12-volt coil. muting functions were included in the

12 march 1974 design. All control functions are provided ternal vfo, to talk himself on frequency by two surplus, 6800-ohm, 55 Vdc relays. using the companion receiver as a moni- One relay, K101, antennas and tor. functions in receiver muting while the other, K102, is used for B+ switching power between transmit and standby (see fig. The 3 50-0-350-volt center-tapped 13). winding of transformer TI02 is used in a

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fig. 8. Block diagram of the 40-meter ssb and CW transmitter. Power input is about 180-watts PEP.

One relay section, K1O1 A, switches conventional full-wave bridge circuit to the antenna between the receiver and provide 750-volts dc for the final ampli- exciter while KlOl B grounds the exciter fier (see fig. 14). The 310-volt supply for output during standby. A third section, the driver is obtained from the center tap KlOlC, activates the receiver's muting after choke-input filtering. The regulated -. relay during transmission. ,210-volt supply is provided by a pair of The second relay switches the 210- 082 regulators in series. Bias voltage for and 310-volt B+ supplies to the final- the 61466s was acquired by reversing a amplifier tubes and the driver, respective- 6.3-volt filament transformer and rectify- ly, via K102C and 'K102A. Another sec- ing the 117-volt winding. A 50k. 10-watt tion, K102B. switches 210-volts to the wirewound potentiometer, R5, is used as speech amplifier, V101, and i-f amplifier, the bias voltage adjust control (see fig. V103, during transmit. This B+ switching 14). is paralleled by a second manual switch- ing network, S104, which is used as a spotting switch. With S104 in the transmit position, activating the PTT switch through S101 or the manual transmitltune switch, S103 picks up the relays and switches the exciter from standby to transmit. With S104 in the spot position the PTT switch and S103 are interrupted and no relay switching can occur, but B+ is applied to

the speech amplifier and i-f amplifier Front panel of the 40-meter ssb and CW through S104B. This spotting function transmitter. Power input is approximately 180 allows the operator, when using the in- watts.

march 1974 13 transmitter construction closes the final-amplifier tubes and the pi The eternal frustration of any ardent network and is made of 1116-inch-thick home-constructor today is finding the aluminum siding with a ventilated top needed parts. Most of the values given in cover. The plate-tuning and antenna- this design can be varied; all the tuned- loading capacitor shafts are brought out circuit and capacitors of the to the front panel with 114-inch couplers tuned circuits, with the exception of the and shaft-extenders. For the sake of vfo, can be changed, of course, if required neatness and compactness I used a rather

+210v FROM K1028 (FIG 13) WWW.RADiOSCAMATORUL.Hi2.RO,005

WWW.GiURUMELE.Hi2.RO

ClOl 5-25 pF NPO ceramic SlOl dpdt toggle switch (lower- (phase balance control) sideband, carrier) K101,K102 surplus 4-pole relays, 55-volt, 5104 dpdt toggle switch (spotting 6800-ohm coil switch) R102 25k potentiometer (carrier ampli- yl01 455.0-kHz crystal (carrier) tude control) Y102 456.25-kHz crystal (lower side- R103 2500-ohm potentiometer band) fig. 9. Speech amplifier and balanced modulator circuits. Complete relay switching system is shown in fig. 12. resonant frequencies are maintained. The elaborate system of universal joints and seasoned builder may have his own gears to angle the shaft of capacitor C107 scheme of chassis layout and wiring, and away from the speech amplifier tube, neither is particularly critical. V101. This system can be avoided if you My transmitter was built into a use a larger chassis or disrupt the 12x10~2-inch aluminum chassis. The straight-line layout by moving VlOl's photographs show the layout. In any socket closer to the edge of the chassis. chassis layout a straight-line approach is Two variable capacitors, C106 and usually best and that is what I used, with C102, were modified for use in this the speech amplifier followed by the design. The grid-tuning capacitor, C106, balanced modulator, the mechanical fil- was originally a 25-pF miniature variable; ter, the i-f amplifier and so on. all but one rotor plate was removed to The power amplifier cage entirely en- achieve the desired resonance range of 7.0

14 march 1974 to 7.3 MHz for one complete rotation. A switch S102. The vfo tank coil was small L-shaped bracket is used to mount closewound on a 112-inch diameter cer- C106 underneath the chassis. amic form and Q-doped several times. The vfo main-tuning capacitor, C102, Finally, the entire vfo was enclosed by an is a modified variable from a surplus aluminum shield. The mechanical precau- ARC-5 receiver. The gear train and gear tions were justified by the excellent vfo reduction ratio used on these capacitors frequency stability characteristics I ob- make them ideal for amateur vfo applica- tained.

WWW.RADiOSCAMATORUL.Hi2.RO

TO BAL4NCEO MODULATOR FLlOl (FIG 91

0 +210v FROM KlOPB

C105 WWW.GiURUMELE.Hi2.RO

01 72 MHz

C102 modified ARC-5 receiver tuning LlOl 12 turns no. 22 enamelled on 112" capacitor (see text) diameter ceramic form

C103 4-25 pF NPO ceramic trimmer L102,L103 29 turns no. 22 enamelled on l12" C104 4-25 pF N500 ceramlc trimmer diameter, slug-tuned form C105 500-pF silver mica (see text for S102 dpdt toggle switch (internal/ex- other values) ternal vfo) FLlOl 455-kHz mechanical filter (coliins 455 FA21 7102) TlOl 455-kHz i-f input transformer fig. 10. Transmitter vfo, i-f and balanced mixer circuits. Colpitts-type vfo circuit tunes from 6.545 to 6.845 MHz. tions. Only one capacitor section is used As mentioned previously, great care in the vfo. Each capacitor section had should be taken to isolate the input and about 100-pF capacitance, and plates output circuits of all rf stages. Particular were removed until the entire excursion attention should be paid to circuit isola- of C102 yielded a vfo range of 6.545 to tion around the mechanical filter as stray 6.845 MHz with C103 and C104 set to capacitative coupling between the input midrange. and output circuits here can significantly All the vfo components were securely reduce sideband and carrier suppression. soldered with short leads to firm tie points. Miniature shielded cable, soldered transmitter alignment to frequent ground lugs, was liberally Aligning the exciter is simple and used in the switching circuitry around should be done in stages, with each stage

march 1974 15 being built and aligned before the next maximum carrier suppression. With a one is started. The speech amplifier needs typical rf probe virtually no rf voltage no adjustment and can be checked by should be recorded at the plate of V103 connecting an ac voltmeter between the when the balanced modulator is properly plate of V101 and ground through a adjusted. series blocking capacitor. Speaking into a Final adjustment of the i-f amplifier is high-impedance microphone should gro- now accomplished with switch SlOl in duce a swing of several volts on the the carrier position. Move the rf probe to meter. the secondary of TI01 and alternately

TO FINAL WWW.RADiOSCAMATORUL.Hi2.RO'AMPLIFIER (FIG 121

FROM 8ALANCED

WWW.GiURUMELE.Hi2.RO/h fig. 11. Schematic for +3lOV FROM KlOZA the 6GK6 driver stage. (FIG 131

C106 approximately 5 pF (25-pF air variable with all plates removed except one L104 28 turns no. 26 enamelled on ~IA" slug-tuned form R107 5000-ohm, 5-watt wirewound potentiometer

Since the mechanical filter has notice- adjust the primary and secondaries of the able insertion loss, adjusting the balanced i-f transformer for maximum rf voltage modulator is best done by monitoring the indication (typically 10 to 15 volts). signal at the output of the 6BA6 i-f Putting the vfo on frequency can be amplifier, V103. A vtvm with an rf probe most easily done by using a well-calibrat- is coupled to the plate of V103, and ed general-coverage receiver. If one is switch S101 is placed in the carrier unavailable, a reasonably accurate grid- position. This unbalances the modulator dip meter can be used to place the vfo and allows the 455-kHz carrier oscillator within the proper general operating range. signal to pass through the mechanical With capacitors C102, C103 and C104 set filter. About 5- to 10-volts rf should be approximately at midexcursion, identify recorded by the probe. Next, tune the the vfo signal using a general-coverage primary of transformer TlOl for maxi- receiver. Inductor L101 may have to be mum rf voltage. decreased or increased in value (by chang- To adjust the balanced modulator for ing the number of turns) if the vfo signal optimum carrier suppression, switch SlOl is far from the desired range of 6.545 to is switched to the lower-sideband posi- 6.845 MHz. Now, with C102 at midrange, tion. This switches in the 456.25-kHz adjust C103 (and C104, if necessary) to carrier oscillator crystal, Y 102, and any rf bring the vfo frequency to 6.695 MHz. voltage measured at the plate of V103 is Temperature compensation was found to due to carrier. Alternately adjusting R102 be unnecessary in my exciter as vfo and C101, the amplitude and phase bal- warmup drift was quite acceptable and ance controls, for minimum rf voltage the frequency stability is excellent. sets the balanced modulator, V102 for If you experience any excessive fre-

16 march 1974 quency drift during warmup, this may be required, values of 10 to 100 pF can be minimized by experimentally adjusting used for C105, while still maintaining C104 to an increased value while check- adequate mixer output. ing on the frequency stability. Generally Once the vfo has been set on the speaking, an uncompensated vfo will drift desired frequency, the balanced mixer to a lower frequency as the temperature can be easily aligned. During these adjust- rises; adding a negative coefficient capaci- ments, be certain that the internal vfo has tance will minimize this. If it is necessary been switched into the circuit. Place an rf to increase the value of C104, be certain probe on pin 2 of the empty driver socket WWW.RADiOSCAMATORUL.Hi2.RO. 3 *v

7?C107 F

FROM DRIVER 2.5 mH lFla I11

WWW.GiURUMELE.Hi2.RO

0 ZIOV FROM KIOZC (NO 13)

C107,C108 400-pF, 1000-volt air variable (see MlOl 0-1 mA meter text) R106 5000-ohm, 5-watt potentiometer (rf sensitivity control) C109 see text 2101,2102 parasitic suppressors, 8 turns no. L105 23 turns no. 22 enamelled, close- 16 enamelled, wound around wound on 1" ceramic form 10-ohm, 1-watt carbon

fig. 12. Power amplifier and rf output meter. Grid and plate current metering may be added if desired.

to reduce the value of C103 to keep the and, with SlOl in the tune position and vfo within the proper operating range. S104 in the spot position, alternately Tuned circuits L102 and L103 were adjust L102 and L103 for maximum rf not adjusted in the conventional bandpass voltage. I measured more than 5 volts rf manner as there was more than enough on the grid of V105 in my unit. drive from the mixer when its output Maximum vfo carrier oscillator rejec- circuit qvas peaked at 7.2 MHz to fully tion is achieved in a similar fashion. power the 6GK6 driver across the entire Leaving the rf probe on pin 2 of V105, 7.0- to 7.3-MHz range of the exciter. The place SlOl in the lower-sideband opera- coupling capacitor, C105, connected ting position, adjust R101, the rejection across L102 and L103 is 500 pF. The control, for minimum rf voltage. The 7360 balanced mixer offered so much 7360 balanced mixer is capable of about carrier oscillator rejection that I opted for 40-dB carrier rejection and the measured maximum mixer output by heavily coup- voltage should be 0.05 volts or less with ling L102 and L103 at the expense of the proper adjustment of R 101. decreased selectivity of these tuned cir- Before aligning the 6GK6 driver stage, cuits. However, if more vfo rejection is be sure the final amplifier tubes, V106

march 1974 17 and V107, are removed from their sock- volts rf on voice peaks. The monitored, ets. Place the rf probe on pin 5 of V106 detected audio should be clear and crisp (or V107) and set the driver control, and without distortion. R 107, at midrange. Now place the exciter Finally, switch the monitoring receiver in the tune mode by switching S101 to to the upper sideband mode and check the tune or carrier position and S104 to sideband suppression. No intelligible the transmit position. Move S103, the upper-sideband signal should be heard. manual tune/transmit switch to the tune With the sideband suppression check position, and with C106, the grid-tuning completed, all the low-level stages of the capacitor, at midrotation, adjust L104 for transmitter have been aligned and only maximum rf voltage. Turning the driver the power amplifier and relative power output control,WWW.RADiOSCAMATORUL.Hi2.RO R 107, should increase the output metering stages need be adjusted.

RECEIVER INPUT (JI. FIG 2)

ANTENNA

fig. 13.WWW.GiURUMELE.Hi2.RO voltage switching and trans- RECEIVER MUTE mitter and receiver fJ2. FIG 71 control circuitry. Relays are shown in the standby (re- ceive) position. Re- sistors R104 and R105 are voltage- dropping resistors, value chosen to re- T - duce 210-volts dc to (FIG 9) 1- TO SPEECH AMPL 1 proper relay oper- ating voltage. measured output to a maximum of about When adjusting the PA stage remember 60 volts rf. Tuning C106 should further that more than 750 volts exists there, and peak the driver output rf voltage. if touched inadvertently, that's more than As a final check of proper alignment, enough to prematurely end a promising the exciter's single-sideband signal should career. Place the 61468 power tubes in be monitored with an amateur-band re- their sockets and connect a high-wattage ceiver. Keep the 6146Bs out of their 50-ohm dummy load to J104. Adjust sockets during this testing. Place SlOl in R105 to supply about -55 volts bias to the lower sideband position, S104 in the the grids of V106 and V107. Set the drive transmit positions and switch S102 to control, R107, to about midrange and the internal vfo. relative power output sensitivity control, Keep the rf probe on the grids of R106, to about one-third. All the other V106 and V107 and loosely couple the operating controls should be set as pre- receiver to L104. With the PTT switch viously described when monitoring the closed and without modulation, virtually exciter's signal, except that switch SlOl no rf voltage should register, indicating should be in the carrier/tune position. good carrier and vfo oscillator suppres- With the PTT switch or S103 closed, sion. Speaking into the microphone adjust C107 and C108, the plate-tuning should give readings of about 35 to 40 and antenna-loading capacitors, for maxi-

18 m march 1974 mum deflection of the relative power 50-ohm dummy load wattmeter or an output meter, M101. Resistor R106, the in-line monitoring oscilloscope can be output meter sensitivity control, should used to tune the PA stage and adjust the be adjusted to keep the meter at about rf output meter. Capacitors C107 and two-thirds deflection at maximum power C108 are then simply adjusted for maxi- output. mum rf output as read on the wattmeter, Finally, insert a dc milliameter in the or as seen by maximum deflection of the 750-volt line, and with SlOl in the carrier envelope on the scope. R106 is lower-sideband position and the PTT then adjusted for two-thirds meter deflec- switch closed, adjust R 107, if necessary, tion at maximum power output. to bring the final amplifier idling current to about 60WWW.RADiOSCAMATORUL.Hi2.RO mA. As an alternative, a operating Operating in either the ssb or CW modes is extremely simple. For both ssb and CW transmission the transmitter is initially tuned up as previously desceibed for full carrier output. To use the exciter independently, S102 is switched to the internal vfo. With S101 in the lower- sideband position, placing S104 in the spot position will allow you to "talk" WWW.GiURUMELE.Hi2.ROyourself on frequency while monitoring your signal with the station receiver. Once on frequency, simply switch S104 to transmit and all operating functions are controlled by the PTT switch. To operate in the transceive mode, connect the receiver vfo output to J105 using a shielded cable and switch SlOl to the external vfo position. The exciter and receiver are now slaved to the receiver's vfo frequency, and ssb operation is the same as in the split function. Although this exciter is primarily de- signed as an ssb unit, it puts out an excellent CW signal. To operate CW, simply tune up for maximum carrier output, then insert a key into J102. Switch S102 is left in thecarrier position and S103 is used as a manual CW/standby switch. 1101 6-volt lamp (power on) L106 10-mH, 175-mA filter choke circuit improvements (Hammond 193J or similar) You may be surprised by the omission R105 50k, 10-watt potentiometer (bias of some operating luxuries in this exciter. control) This was intentional - to keep design and TI02 117-Vac power transformer. 350-0-350. 6.3 Vac secondary alignment as simple as possible and to (Hammond 273BX or similar) keep cost at a minimum. However, vox T103 117-Vac filament transformer, and sidetone circuitry could be easily 6.3-Vac secondary (Hammond added for voice-operated ssb operation 166L6 or similar) and semi-break-in CW operation. fig. 14. Power supply for the 40-meter ssb and For those of you who may want to use cw transmitter. upper sideband on 40 meters, switch

march 1974 19 WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

Top view of the transmitter chassls. Power amplifier cage is upper rlght, next to the power supply. Vfo enclosure is lower left, next to the front panel. Speech amplifier tube is underneath the antenna-loading capacitor shaft to the extreme right.

5101 could be changed to a 3-pole unit to added to monitor final plate current, switch in the required 453.75-kHz plate voltage and grid current. And. for crystal. If you thrive on the sight of the few courageous builders who seek still swinging meter needles, appropriate more, multibanding this exciter might switching and metering could easily be even be considered. Changing vfo fre- quencies and switching in separate mixer and driver coils would be the most simple means of adding 80- and 20-meter opera- tion. For the higher frequencies, a second frequency conversion scheme would probably offer the best results.

references 1. Doug DeMaw, WlCER, "Building a Simple Two-Band VFO," QST. June, 1970, page 20. 2. Doug DeMaw, WICER, "A 40-Meter CW Receiver," QST. January, 1973, page 1 1. 3. The Radio Amateur's Handbook, 50th edi- tion, 1973, ARRL, Newington, Connecticut, page 258. 4. James Trulove, WBSEMI, "Three-Terminal Underneath the transmltter chassls. Front of Voltage-Regulator ICs," ham radio, December, chassls is at bottom. Power supply components 1973, page 26. are in upper right-hand corner. ham radio

20 march 1974 -v 1 ---.- -,- NE ANSMITTER -ILLS FOR WWW.RADiOSCAMATORUL.Hi2.RO LEASS THAN A DL-AR 'ER WATT WWW.GiURUMELE.Hi2.RO

THE SWAN 600T! There are five transmitters available to is $1.41 per watt; the 200 watt rig with the amateur radio operators today providing 5- power supply built-in runs $2.30 per watt, band coverage in SSB, CW and AM modes. while the other 200 watt transmitter costs Of these five, only SWAN'S 600T supplies $2.65 per watt by itself or $3.15 per watt if 600 watts P.E.P. input. Among the others, you buy the power supply recommended. one has 240 watts P.E.P.; two have 200 watts Now consider the economical SWAN 600T P.E.P. (one of these requiring an accessory - it gives you a full 600 watts P.E.P. input, power supply); and one is a kit capable of a about three times the power of the others, mere 180 watts P.E.P. input. for JUST 98d PER WATT! Compare the cost per watt, then judge for The brand YOU should buy is obvious. yourself as to which is the best value: The Visit your authorized SWAN dealer and order kit retails at $1.67 per watt; the 240 watt unit your 600T.

WHEREVER THERE'S VALUE IN AMATEUR RADIO, YOU'LL FIND SWAN ELECTRONICS 600T Transmitter ...... 600R Custom Receiver ...... 600R Custom Receiver with DEALERS THROUGHOUT THE WORLD SS-160 filter ...... or order d~rectfrom 600s Speaker ...... 600SP Deluxe Speaker with SwmIY FP-1 phone patch...... Q ELECTRONICS 510X ...... l"", n., ,0 l Doear 0" VX-2 Automatic Voice Control dome Off~ce:305 AlrDort Road. Oceans~de.CA 92054 MARK II Linear Amplifier Teleohone (714) 757-7525 (2000 watts P.E.P.) ...... $679.95 THE BEST PRACTICAL DEVELOPMENTS IN AMATEUR RADIO

More Details? CHECK-OFF Page 94 march 1974 21 WWW.RADiOSCAMATORUL.Hi2.RO

automatically controlledWWW.GiURUMELE.Hi2.RO access

open repeaters

unwanted transmissions. Even if the input frequency is less popular, the growing availability of synthesizers puts an un- A control system guarded repeater at the mercy of the operator who can't resist seeing how that automatically guards many squelch tails he can generate and how many identifiers he can trigger each time he pushes the button on his micro- against interference phone. WREIABC, the 146.16176 repeater while allowing serving the Cleveland area, is located on the crest of a ridge southeast of the city. open repeater operation There are 16/76 repeaters to the east, at Ashtabula, to the south at Newcomers- town and Columbus, and across Lake Erie in Detroit. Even without a band opening, mobiles in the fringe areas between re- Anyone trying to operate an open re- peaters often key more than the machine peater on one of the popular frequency - with only a slight propagation enhance- pairs such as 146.16176 in an area like ment the situation can become chaotic. northern Ohio is increasingly faced with a The Detroit repeaters, Great Lakes on difficult choice: guard the input, and shut 146.16176, and DART on 146.04164, out the visitor or occasional user who have adopted sub-audible tone access, or lacks the required means of access, or full-time private-line. The Ohio 16176 leave it unguarded and expose the re- repeaters have established secondary in- peater to a lot of plucking and other puts on discrete tertiary frequencies (for

22 march 1974 example, 146.355 in Cleveland) to permit made it possible for a fringe area station base stations and high-powered mobiles in to picket-fence the repeater indefinitely the fringe areas to select the repeater they as long as his signal was strong enough to want to access. open the receiver squelch once every five seconds, which was hard on the equip- the problem ment and even harder on the control The group that operates WR8ABC has operator. More than once the repeater has consistently voted to keep the repeater as been out of service for several hours open as possible.WWW.RADiOSCAMATORUL.Hi2.RO When conditions made because a control operator switched it off it necessary to guard the 146.16-MHz and forgot to turn it on again when the input, provision was made for access with interfering signal disappeared.

KEYING SIGNAL FROM OUTPUT OF SHAPING CIRCUIT (SEE FIG 21

WWW.GiURUMELE.Hi2.RO

2 13

*FILTER CAPllClTORS IF NEEDED. IKE rExn

fig. 1. Timing circuit and counter for the repeater control system. For values of R1. R2 and C1, see text. All diodes are general-purpose silicon types such as the 1N914.

private-line (110.9 Hz), tone burst (2000 the solution Hz) and the 1336-Hz tone generated by a In an attempt to overcome some of Touch-Tone pad. In addition, once the the disadvantages of the previous method, guard was opened by one of these means, a new system to control access to the the repeater remained open to access by 146.76-MHz input has been installed any on-frequency carrier for the duration which leaves the input open until it is of each transmission and five seconds repeatedly keyed by a signal which is not thereafter. modulated by any of the access tones Permitting "tail-ending" in this way recognized by the decoder. When the effectively opened the machine to use by receiver squelch is operated three times in any number of stations, with or without succession by such a signal the input is private-line or tone generators, as long as automatically guarded. The guard is one of them could whistle the machine opened, also automatically, by a timer in up in the first place. Unfortunately it also approximately 15 minutes; it opens

march 1974 23 sooner if the repeater is keyed by a line tone. The inputs to the other three station using an accepted access tone, or diodes are normally high, and are by one using the unguarded secondary switched to ground potential when an input. activating signal is received. The circuit is shown in fig. 1. The BD If no signal is received from any of the input of an SN7490 decade counter, Ul, four sources connected to the diodes for is toggled by a signal source that goes a predetermined interval, the timer con- high each time the guarded receiver COR nected to the second input of gate U2C will reset the output counter. The timer is another decade counter, U3, driven by WWW.RADiOSCAMATORUL.Hi2.ROthe square-wave output of an lntersil 8038 precision waveform generator, U4. SIGNAL W COUNTER INWT The rate at which the 8038 cycles is (SEE FIG I) RECEIVER I controlled by the values of C1, R1 and R2. As installed at WR8ABC, C1 = 100 pF, R1 = 47k, and R2 = 100 ohms. The SAME SIGNAL TO KEYlNG SIGNAL generator cycle is just under two minutes, INPUT IN FIG 3 and U3 reaches the count of 8 in 15 minutes, at which time it resets itself and WWW.GiURUMELE.Hi2.ROU1. fig. 2. Shaping circuit for the keying signal. construction Note that the 2.2k load resistor con- is triggered by a signal. It counts the nected to pin 9 of the 8038 is returned to pulses generated by a signal with no +5 volts rather than to +12 volts to make access tone, and latches in the "binary 9" the square-wave output TTL compatible. condition on the fourth count. This Some precautions in construction are generates a logic 1 at the A output, pin advisable. Rf shielding is essential if the 12, until the counter is reset to zero. unit is to be installed near a transmitter, To make the counter operate in this although there should be no problem manner the D output, pin 11, is wired to with a split-site repeater. The count and one of the Rg reset inputs, and the other reset inputs are all sensitive to short Rg input and one input are control- Rq pulses. Signals connected to the PL and led by an SN7402 NOR gate, U2. So long as one Ro and one Rg input are low, U1 counts the receiver COR cycles. On the fourth count the D output at pin 11 carries the Rg input at pin 6 high. If pin 7 is also high, the counter latches with both A and D outputs in the high state. It will remain in this condition until the second Rg input, pin 7, is switched to the low state by gate U2C. The same signal that does this switches the output of gate U2B high and U1 resets to zero. The impulse to reset the counter to zero can come from any one of the four sources connected to the resistor-tran- sistor network through diodes CR 1 through CR4. The private-line (PL) out- put from the WR8ABC PL decoder is low Front and rear views of the printed-circuit when the receiver is squelched and high board used for the repeater access system. The when the squelch is opened by a private- relay is not mounted on the board.

24 march 1974 tone inputs that reset the unit should be WR8ABC repeater is built on a home- filtered to suppress response to transients, made PC board approximately 2x4 and so should the signal from the second- inches, which provides for all the com- ary receiver COR. A small electrolytic ponents in figs. 1 and 2 except the COR capacitor or a resistor and capacitor relay. Boards for the later model shown should suffice. in the photographs, which includes the The keying signal to the counter input optional input filters, and/or complete is more critical. COR relay contact assembled units are available from the bounce can cause erratic counting. The author.* WWW.RADiOSCAMATORUL.Hi2.RO ACCESS CONTROL

fig. 3. Transmitter control re- lay circuit. Values of R3 and R4 are selected as described in text. Transistor Q3 is a pnp silicon transistor capable of SHAPED KEYING switching the relay current SIGNAL FROM and voltage. Diode CR5 must FIGURE 2 have a PIV rating higher than the positiveWWW.GiURUMELE.Hi2.RO voltage supply. best way I have found to shape the COR conclusion signal is shown in fig. 2. This system uses To summarize operation of a repeater two sections of an SN7400 NAND gate with this system of access control, so long and a double-throw COR relay on the as no more than three successive signals receiver. without access tones key the transmitter The unit was designed to work with through the guarded receiver in any the solid-state control logic described in 15-minute period, the guard will remain an earlier article,l but the output can be open indefinitely. It will close immediate- used to drive any TTL-compatible logic, ly, however, when the guarded input is or to operate a transmitter keying relay plucked three times, accidentally or on with a transistor driver. A circuit to do purpose. A visitor to the area, without this using the other two sections of the tone access, never has to wait more than SN7400 is shown in fig. 3. Transistor 03 15 minutes for the repeater to open up, is a pnp silicon switching transistor capa- and since he is usually answered by a ble of handling the keying relay current station using PL, tone, or the secondary and voltage. Resistor R3 should be selec- receiver, can carry on a conversation ted to limit the current through it to indefinitely in most instances as though approximately 10 mA when the junction the repeater was unguarded. of R3 and R4 is at ground potential. Resistor R4 should limit the voltage at reference this junction to between 3.5 and 5 volts 1. R.B. Shreve, WBGRG, "I ntegrated-Circuit when the junction is ungrounded. Diode Sequential Switching for Touchtone Repeater CR5 protects 03 against surges when the Control," ham radio, June, 1972, page 22. relay opens. The access control on/off ham radio switch, which can be a remotely control- led flip-flop or relay, permits the operator "Epoxy printed-circuit boards can be purchased to inactivate the guard circuit if a com- from the author for $5.00, postpaid. Prices on complete units, with any reset time interval up pletely open operation is desired at any to 30 minutes, and designed to interconnect time. with the user's equipment, will be quoted on The original unit in service at the request.

march 1974 25 WWW.RADiOSCAMATORUL.Hi2.RO

six-meter frequency synthesizer

regulations, and crystal control became mandatory. WWW.GiURUMELE.Hi2.RORock-bound transmitters forced de- velopment of improved vacuum-tube vfos over the years, and these gradually gave Complete I way to solid-state circuits. Heterodyne 0 versions improved on them in turn and construction details now, with the "galloping IC Tech- nology," synthesizer frequency control is for a coming on strong. Widely used in military and commercial equipment for many years, until recently frequency synthesis frequency synthesizer u a has been too costly for general ham use. v, However, two-meter units are now on the $ market and a number of construction that covers the entire C C articles have appeared in print for the do-it-yourselfers. 50-MHz band s 2 Recently, I had a go at working up m one of these exotic channelizing vfos for 0 in 1-kHz steps PC a 50-MHz a-m rig. New and unusual 2 circuit problems had to be solved before L success was attained. For the unwary v, homebuilder who is or will be building an 5 indirect synthesizer, this article will en- Y deavor to point out some constructional Although I have been relatively inactive 5 pitfalls, offer a few guidelines and, hope- on 6 meters in recent years, this band has fully, aid in maximizing proper operation always been a favorite. This is no doubt 5n on your first try. 0 due to an austere but exciting ham design beginning on 5 meters during the 1930s when modulated oscillators, superregen 2 Following a modest literature search, a 6-meter IC frequency synthesizer was receivers and Pickard antennas were com- 'E,c mon. After World War II modulated c blocked out that tuned from 50.000 to oscillators were phased out by stability 54.000 MHz in I .O-kHz steps. Considera-

26 march 1974 tion was given to minimum steps of 5 or enameled , a handy enameled hookup 10 kHz, knowing it would ease the task wire with insulation which melts back of phase-locking and reduction of spuri- from hot solder to leave a nicely tinned ous outputs, but this less desirable trade- end ready for connection. Feeding in off was finally overcome by intensive clock pulses having a configuration called debugging. To be useful as an 8-MHz for by the chip manufacturer at a crystal replacement, output frequency 8,333,330 Hz rate resulted in an output runs from 8,333,333WWW.RADiOSCAMATORUL.Hi2.RO to 9,000,000 Hz. that closely resembled a pseudo-random An electronic calculator made quick work bit stream! "Oh well!" said I, "probably

WWW.GiURUMELE.Hi2.RO

fig. 1. Programmable divider divides from 50,000 to 54,000 in steps of 1. The thumbwheel switch assembly (Sl. 52. 53 and S4) is an EccoSwitch type 4R177612G. Switch 55 provides divide-by-4 for MARS netting (see text). of the math. Frequency increments of just a wiring error, maybe a stray oscilla- 166.213 Hz, when multiplied by 6, yield tion or a bit more B+ bypassing." 1.0-kHz steps on 6 meters; the required Three weeks later, the output wasn't division is 50,000 to 54,000. A 1.0-MHz quite so random but counting down to reference crystal divided by 6000 pro- zero from a given input frequency never duced the necessary 166.2/3 Hz compari- agreed with the divider truth table. Even son signal for phase detection. getting close to 166 Hz required a higher First off, a string of five 74192 pro- input frequency than theory said was grammable divider ICs were plugged into necessary. The B+ supply from a three- sockets Duco cemented to perfboard and terminal IC regulator had to exhibit very wired to divide by 50,000 as shown in fig. low impedance. Miniature axial-lead tan- 1. This wiring consisted of no. 28 Beldsol talum capacitors added for supply voltage

march 1974 27 bypassing helped a little, but it was just extra counts. My skinny little magnet impossible to obtain a stable, fixed divi- wire must have looked like kilohms! sion ratio. Not wishing to process double-clad About this time K20AW described his printed-circuit board, and with low cost programmable divider.1 After some read- always in mind, the socketlperfboard ing, the operating principles of K20AWrs layout was modified to accomodate 3M's circuit became clear. Since I only had 1181 half-inch wide, copper-foil adhesive transmitter frequency control in mind, tape, one pattern stuck down for ground his circuitry for receiver LO use could be and the same pattern directly opposite deleted. Also, WWW.RADiOSCAMATORUL.Hi2.ROsince the most significant for B+. This formed a low dc resistance,

+5v +sv +5v +5v

f5V

14

166 2/3 Hz

0+5V WWW.GiURUMELE.Hi2.RO

+ 7OV AT 50 MHz + 2 IV AT 54 MHz C5TO38VMAX

TO FROM PIN 8 VCO (FIG 3)

fig. 2. Circuit for the 1-MHz reference oscillator, divide-by-6000 and MC4044P phase detector. Ql and 92 may be any small npn transistors with current gain of at least 100 such as the 2N4124 or 2N5130.

digit never changed, a 7490 wired bi- low inductance and distributed bypass quinary could divide by five. capacitance power feed system that also This new circuit replaced the first made socket wiring easier. When fired up version and at least got me into the once again, the long sought after magic ballpark, meaning division was off by numbers appeared! only scores of numbers instead of hun- Dividing 8,333,330 by 50,000 gave dreds! Many troubleshooting tricks were 166.6 Hz, and dividing 9,000,000 by tried and failed. Finally, a fruitful discus- 54,000 also gave 166.6 Hz. Various in- sion with WAlCTS yielded a nugget between divisions were tried; all came generally known to computer builders out correctly. This without any B+ by- but seemingly little known among ama- passing to ground, too. Success was so teurs: B+ and ground for TTL logic sweet, the foil transmission line im- should use ground-plane techniques with pedance never did get measured. How- a 100-ohm transmission line built in for ever, 4.2 pF per half square inch of foil power distribution. Neglect of this basic was measured and with 20 inches per design requirement was manifested in board this is 168 pF. As a rule of thumb,

28 march 1974 pulse rise time can be related to one cycle of rf in the same period, so the 5-nano- second transitions correspond to 200 MHz where 168 pF has a reactance just under 5 ohms. Obviously, this is quite effective in shunting pulses whose source impedance is 10 to 20 times higher. With an idealized clock pulse obtained from a lab pulse generator the next item of business was toWWW.RADiOSCAMATORUL.Hi2.RO simulate it inexpensive- ly. A 74121 one-shot, timed to deliver 40-1-1snegative-going pulses, was found to

be perfectly adequate. Proceeding next to Small size of the circuit boards used in this the reference circuit and again using synthesizer results in a very compact package. copper foil for power distribution, a 1.0-MHz crystal oscillator divided by graphed tuning curve shown in fig. 4. This 6000 was constructed (fig. 2) and never check should always be made to get an failed to operate properly from first idea of linearity and voltage swing re- turn-on. WWW.GiURUMELE.Hi2.ROquired for a given configuration. When tuned in on a CW receiver, the VCO carrier jumped in discrete steps as the pot As other writers have indicated, the wiper moved along individual turns of vco must be inherently stable by itself winding resistance which is understand- before electronic frequency control is fed able when it is realized that slew sensi- back. A Vackar oscillator circuit was tivity is about 500 Hz per millivolt. Slow chosen for three reasons: it is frequency frequency drift is not important during and amplitude stable, and, like the Clapp, this test but any audio rate burble must has one connection where small capaci- be eliminated. Some diodes work tance variations result in large frequency well as tuning devices but be careful of shifts. The circuit, fig. 3, was built on a ambient light effects; one diode I tried bit of double-clad printed-circuit stock to had a translucent plastic case which insure mechanical integrity and simplify caused 60 Hz fm from an overhead light shielding. It was then tested by feeding in until the device was wrapped in black varactor bias from a 10-turn 10k pot tied plastic tape. across 5 volts of B+. Tuned-circuit com- Oscillator B+ must be essentially Donent values were .juggled -- to obtain the battery-pure and stable, and a separate 7805 IC voltage regulator is recom- mended. No doubt a pA723 regulator could be used, but these new three- terminal voltage regulators are so easy to wire in, they spoil you for anything else. Unilateral amplification is necessary to prevent spurious vco pulling by logic pulses sneaking back through the gain chain. The resultant pulsed fm generates a wide spectrum of hash that is impossible to cure without redesign. A Darlington Layout of the reference divider, showing the emitter follower has worked well in this use Of 3M adhesive-backed copper tape to regard and is able to properly fire the achieve the low-impedance B+ and ground leads one-shot. Additional isolation and gain is required for proper operation of the TTL logic. Circuit board for the programmable divider (fig. provided a MC1350P which drives the 1) uses the same technique. transmitter multiplier.

march 1974 29 phase detector during a second effort. After considerable Next on the agenda was selecting and playing around with component values, optimizing a phase detector circuit. Per- sidebands were down to about 20 kHz. haps it would be helpful to set up an One bad feature was the lack of drive idealized specification and then see what toward sync if the vco happened to get can be done to meet it in the real world. outside one end of lock range. For all its This black box would detect the slightest faults, a MC4044 IC always drove difference in phase of incoming 166-Hz towards lock, no matter where the vco pulses, change this information into a was initially. precise step of dc control voltage and Since W1 UY K's circuit3 worked on instantly slew WWW.RADiOSCAMATORUL.Hi2.ROthe vfo back into exact 41-Hz pulses I decided to give it a try. It synchronism with its reference. In truth, was wired in per his schematic and since nothing works in zero time, there showed promise right away; sidebands

WWW.GiURUMELE.Hi2.RO

fig. 3. Circuit for the vco used in the 6-meter frequency synthesizer. The 9.35 pH inductor. L1, consists of 37 turns no. 22 enamelled on a T-68-2 Amidon toroid core. would have to be some phase difference came down to about 10 kHz. Another to produce a correction voltage, and steps period of testing commenced in an at- of dc voltage generate wideband tran- tempt to modify the circuit for this sients. Therefore, a real world circuit will particular synthesizer. The final result is necessarily have time delays, small error similar with one interesting exception - signals and low pass filtering as minimum the use of a 10k variable for adjusting requirements. loop lock-up rate. The first circuit I tried2 was totally As resistance is progressively reduced, unsuited for low-frequency use; the vco vco slew response changes from over to put out a spectrum of hash many hun- critical to under damping and eventually dreds of kHz wide and optimization only into sustained hunting. It's quite easy to reduced this to about 90 kHz. For audio- hear this effect on a CW receiver and frequency phase detectors, many design- adjust for a rapid settling time (about 2 ers have gone to sample-and-holdcircuits seconds) by placing a finger momentarily as a means of reducing pulse feedthrough, on the vco tank coil to force it far out of but since I didn't have any enhancement- lock. Do this at 8.33 MHz where loop mode fets on hand, a pair of MPSA12 gain is highest. Darlington transistors were substituted Settling time is a little longer at 9 MHz

30 march 1974 due to slightly lower voltage sensitivity frequency signals could take place. To and is a tradeoff made for non-linear prevent this, a simple pulse-width com- varicap pull range. A low leakage elec- parator, timer and relay deactivate the trolytic must be used for the 25-,uF transmitter and hold it off until sync is capacitor (20 megohms on a Simpson regained (see fig. 5). Two NAND gates 260) because it connects between a pos- make up a one-shot whose timing capaci- sible maximum 4 volts and a dc amplifier tor produces one microsecond for every having a current gain of about 50,000. 770 pF, so .O1 ,uF gives about 12 micro- Only ac coupling is wanted. An RC filter seconds. This is longer than the normal follows the active filter to reduce side- up-to-5 microseconds out of the first bands to essentiallyWWW.RADiOSCAMATORUL.Hi2.RO zero and at 40 dB gate. These two signals take turns keeping over S9, the carrier sounds perfectly inputs low on a third gate and its output quiet. stays high. Should the vco suddenly shift In a lab check using a special oscilloscope, varicap control voltage 3.0 showed 10 microvolts pulse and about 30 ?22-5- microvolts random dc -3 on a plus I.O-volt g 20 pedestalWWW.GiURUMELE.Hi2.RO at 8.5 MHz. &

fig. 4. Frequency of vco vs control voltage, using a 0 5 Sylvania 1 N4005 rectifier BP 83 84 85 86 87 8.8 89 9.0 91 as a varactor. FREQUENCY (MHZI

This equates to an average carrier uncer- frequency more than 10 kHz at 6 meters, tainty of +7 Hz or six times that on 6 the 5-microsecond pulse briefly becomes meters, an acceptable figure for most longer than the 12, gate output drops, transmission modes. These small error firing the timer and energizing the relay voltages remain unchanged, but the major for 4 seconds. Consequently, a frequency dc voltage will lie between 0.5 and 3.8 change of several kHz is possible without volts, depending on frequency and trim- initiating action. mer capacitor adjustment (0.7 at 50 MHz A desired frequency shift tolerance and 2.1 at 54 MHz used here). may be set in by variation.of the one-shot A simple but revealing test can be capacitor while off time is changed by made by tuning in the reference crystal's appropriate shift of R or C in the NE555 9th harmonic at 9.0 MHz, then setting in timer. Start-up, long settling times or a division of 53,999 to produce a 166-Hz hunting will keep the relay on; it will not heterodyne. Servo loop limitations will be reset until phase lock is effected. evidenced by a small burble or beat note construction instability. Any circuit modifications should be aimed at minimizing this ran- If you decide to build this six-meter domness without degrading sideband frequency synthesizer, there are several levels or lock-up action. important points to keep in mind. First of all, use a ground plane or copper strip unlock detector for logic B+ and ground power distribu- If the synthesizer becomes unlocked tion. Strive for battery-pure dc supplies for any reason, transmission of off- for the oscillator and buffer. Use at least

march 1974 GI/I 31 WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO fig. 5. Circuit of the unlock detector and timer. Relay K1 is a Sigma 62R2-12DC. Simple three-terminal five-volt voltage regulator for the entire synthesizer is shown at right, below. two voltage regulators: One for logic, one do fine. If only the first MHz on six for the vco. Zener diodes have too high meters is of interest, adjustment is that impedance and unregulated B+ is out of much easier. Experiment with different the question. voltage-variable capacitors. A Sylvania Keep the dialed logic wiring short and IN4005 rectifier diode produced less direct to its respective IC terminal. Opti- frequency jitter than a Motorola Epicap mize the base-bias resistor in the vco MV2209. using the 9-MHz burble test (use a 22k For a real eye-opener, try placing a isolating resistor and 250k pot in series to battery-powered broadcast radio next to determine the proper value). Follow the the programmable divider board to pick vco with one-way rf amplification. up its amazing spectrum of signals. Then, Shield the entire synthesizer. Shield the oscillator separately, and use feed- through capacitors and shielded cable. Beware of ground loops - non-reducible sidebands usually result. All construction must be mechanically secure. Anything that moves will cause phase shifts that the detector tries to correct for. Think of phase as a change of less than one-half Hz at 8 MHz! Stray capacitance at the varicap con- nection will have considerable affect on the capacitor values required to bracket 8.3319.00 MHz with a given tuning diode and bias voltage swing. A frequency counter is convenient, but a well- construction of the vco. The 9.35-p~inductor calibrated communications receiver will is in the upper left-hand corner of the board.

32 march 1974 "finger test" the vco - the result is hard to believe! summary NEW Troubleshooting this synthesizer was a real challenge but definitely worthwhile once it began to operate correctly. There is tremendbus satisfaction in having a 6-meter crystal-stable rf generator with 4000 discrete frequencies. Great for nets, receiver calibrationWWW.RADiOSCAMATORUL.Hi2.RO and avoiding inter- RANGER ference. When asked to move "up a couple," you'll shift exactly two kHz. for Amateur FM Schedules on a prearranged frequency Get extended range will be right on. Other vfos can be with this exciting new antenna. A one eighth wave phasing stub and three half waves in -.$AOPERATE phase combine to con- WWW.GiURUMELE.Hi2.ROcentrate your signal at LI the horizon where it can do you the most goad.

6.3 dB Gain over 1/4 wave whip 4.5 dB Gain over 1/2 . L) wave dipole ARX-2 146-148 MHz fig. 6. MC1350P rf amplifier provides 0.3-volt $22.50 rms output into 50 ohms. L1 is 19 turns no. 28 on 3/6" diameter iron-core form. 3/4" long. L2 ARX450 435450 MHz is 6 turns no. 28 over center of L1. $22.50 ARX-220 220-225 MHz calibrated by your dialing in spot fre- $22.50 quencies to zero in on. MARS netting is Extend your present possible by adding a toggle switch on the AR-2 Ringo with this 7490 bi-quinary to divide by four; see the RANGER KIT. Simple in- schematic in fig. 4. Narrow-band fm is stallation. possible by adding modulation to the vco control voltage, but hum will be a prob- lem as only tens of microvolts can be tolerated.

references 1. P.A. Stark; K20AW, "Frequency Synthesizer for Two-Meter FM," 73, October, 1972, page 15. 2. K.W. Robbins, W1 KNI. "Tunable Six- and IN STOCK AT Ten-Meter Phased-Locked Loop," ham radio, January, 1973, page 40. YOUR LOCAL DISTRIBUTOR 3. D.H. Stevens, WlUYK, "A 4000Channel TwoMeter Synthesizer," QST, September, 1972, page 17. ham radio

march 1974 33 performance characteristics of WWW.RADiOSCAMATORUL.Hi2.RO vertical antennas

tall verticals have much better low angle radiation than short ones, reference to antenna books such as those written by A discussion of Kraus2 or Jordon3 show that the low- angle radiation pattern is essentially the same for a wide range of vertical heights. WWW.GiURUMELE.Hi2.ROmatching networks, More on this later. My studies show that earth and net- network losses I.$ work losses are the most important fac- .- tors. These losses are greater for short c verticals than they are for tall verticals. and bandwidth of 3 +.'o I've indicated a few considerations, but there are still a number of questions vertical antennas to consider and answer, and in more detail. How high should the vertical be? Is c. of various heights c a tall vertical better than a short one? If 2 so, how much better? What does better mean, or what factors or tradeoffs are 5 important, and what is their relative importance? $ You will find that there is quite a bit of choice in the height that may be used I've been interested in antennas for C 80-meter DX that were simple, inexpen- i for a single vertical. If two or more sive and effective, so I've been reading a g verticals are to be part of a phased array, lot of the vertical antenna literature prior then there is less choice as to which to putting up a vertical or a phased .-g antenna height may be used. vertical array. I chose verticals early in c Some of the factors that must be 0 this effort since antenna books show that b considered are self-impedance; mutual im- 0 the low angle radiation from vertical 2 pedance in arrays; earth, radial, and net- W monopole antennas is considerably better work losses; bandwidth and vswr versus than from horizontal dipoles unless the height; vertical radiation pattern; type of dipoles are unreasonably high, at least for tuning network required; type of trans- 80 meters. mission line used; physical or mechanical The first question was, "What vertical 3 factors; and the radial ground system. height should be used?" A recent article1 rJ How can you make sense out of so shows that short verticals do a pretty many interrelated factors? You don't good job, which I agree with. Although n want to reinvent the wheel, so I will make 0 some antenna articles have indicated that K use of material such as that from early

34 march 1974 issues (1930s) of the Proceedings of the antenna self impedance IRE, and from standard antenna text- The electromagnetic field produced by books. Today there are a number of new an antenna results from certain current tools at our disposal such as digital distributions on the antenna which vary computers, pocket electronic calculators, with time. Many cases are analyzed in the etc., and these were used to develop literature, from the elementary current answers to some of the questions. element, to the elementary dipole, to a Rather than try to answer all of the full-length dipole with sinusoidal current questions at once, several articles are distribution. Various steps in the analysis planned, with only a few topics in each. show that induction, radiation and elec- The data and examples will cover a range WWW.RADiOSCAMATORUL.Hi2.ROtrostatic fields result, all of which fall off differently with distance. All of these fields (the near field) must be considered to determine either the reactance of a single antenna, or the mutual impedance between two or more antennas. The radiation field is sufficient when considering the radiation patterns. These theories were used by authors of antenna books and articles to develop equations WWW.GiURUMELE.Hi2.ROused to make calculations here. I used the appropriate formula from Jordan2 for antenna self impedance (one for resis- tance and one for reactance). Each BASE REACTANCE, X (FOR 2-INCH DIAMETER PIPE1 formula is a long complex expression consisting of many sine and cosine in- tegral terms, and they are also functions of antenna height. fig. 1. Vertical antenna Antenna self impedance, as used here, base impedance as a func- consists of the antenna base resistance, R, -4m tion of the height-to-wave- and the antenna base reactance, X. You -1 i length ratio. must be careful when using such formulae to be sure that loop or base values are of values which are practical for average used consistently and properly. The base amateur situations. The graphs will be impedance values are those seen at the large enough to serve as useful reference data for amateurs who wish to work out other examples. This first article will deal with the self impedance of a single vertical, and indicate what networks (if any) are required for various heights of verticals, what losses occur in these networks, and what band- widths result. The second article will compare the Po : 6W WATTS COIL 0 Pa) vertical radiation patterns of various height verticals. The third article will discuss ground losses, and answer the remaining questions posed here. The last 10 20 26 40 50 60 article will present mutual impedance ANTENNA HEIGHT (FEET) data, and will analyze a particular phased fig. 2. Network coil loss vs antenna height (See array. text).

march 1974 35 base of a vertical antenna. Loop values table 1. Calculated vertical antenna characteristics vs result from considering the current loop height, and vswr performance with three different types of matching systems. up on the antenna. It is easy to convert from one set of values to another, as for 1. No matching network (center of coax connected directly to antenna base). example HA (feet) hlh R X coax vswr 80.0 0.325 90.6 +230.0 RG-11/U 8:l Antenna textbook data is sometimes 76.0 0.31 75.0 +180.0 RG-11/U 8:l given for loop values, and sometimes for 60.0 0.243 33.8 + 5.7 RG-11/U 2.2:l base values. Base values are used here. 70.0 0.285 55.0 +108.0 RG-8/U 6:l 69.0 0.28 52.0 + 95.0 RG-8/U 5:l WWW.RADiOSCAMATORUL.Hi2.RO61.5 0.25 36.6 +21.3 RG-8/U 1.8:l 60.0 0.243 33.8 + 5.7 RG-8/U 1.5:l 59.3 0.241 32.0 0 RG-8/U 1.6:l where h is the wavelength, and h is the electrical length of the antenna in wave- 2. Series capacitor. C, between coaxial transmission lengths. line and antenna base. HA antenna height (feet) h/h R X coax C,pF vswr Another time you must be careful is 80.0 0.325 90.6 +230 RG-11/U 182 1.2: 76.0 0.31 75.0 +I80 RG-11/U 233 1.0:; when you calculate the physical length of 70.0 0.285 55.0 +I08 RG-8/U 388 1.06: the antenna.WWW.GiURUMELE.Hi2.RO For antennas of the di- 69.0 0.28 52.0 +95 RG-8/U 441 1.0:. ameter of interest (2-inch diameter con- 61.5 0.25 36.6 +21.3 RG-8/U 1966 1.4:. duit was used here), the physical length should be 5% less than the electrical 3. Type-C L-network (see fig. 3) used with RG-B/U length. The computer calculations were coaxial cable. Vswr 1.0:1. made using the electrical length in order HA to compare my results with standard (feet) hlh R X L.PH C.PF antenna textbook data, but the physical 60.0 0.2433 33.8 5.7 0.80 591 lengths given here will have the 5% 50.0 0.2028 20.7 -86.5 4.69 991 40.0 0.1622 12.1 -183.8 8.62 1467 shortening included. A handy formula for 30.0 0.1216 6.3 -303.0 13.41 2164 this is

984 x hA 4. Type-A L-network (see fig. 3) used with RG-B/u HA = feet FMHz x 1.05 coaxial cable. Vswr 1 .O: 1. HA where HA is the physical antenna length (feet) hlh R X L,PH C.pF in feet, and hfi is the electrical length in 70.0 0.285 55 +lo5 4.33 637 fractions of a wavelength. For example, if FMHz = 3.8, then HA = 246 hh. Then, if Table 1 lists these choices, the net- hA = 0.25, HA = 61.5 feet. work used (if any) and the resulting vswr The results of the first computer pro- calculations made at 3.8 MHz. This data gram I wrote gave values of R and X vs shows that with no network and hA. This standard data is reproduced in RG-11/U transmission line, the lowest fig. 1 for use in selecting some examples vswr is 2.2:l with HA = 60 feet. With no of practical heights of verticals. network and RG-8/U coax, the lowest The antenna lengths selected for con- vswr is 1.5:l with HA = 60 feet. If the sideration were even multiples of 10-foot proper series capacitor is used, the vswr is pieces of conduit, and specifically were 1.0:l for RG-8/U at HA = 69 feet, and 30-, 40-, 50-, 60- and 70-feet long. Some for RG-1I/U at HA = 76 feet. special lengths were also selected, and For antennas of other heights the vswr these were lengths which were easily is 1.0:1 if the proper L-networks are matched to RG8IU or RG-11/U coaxial used. The L-networks were calculated cable. using the methods outlined in my QST

36 march 1974 article," or from the methods detailed in current in the coil and antenna is then ham radio. 5 I = = dx = 8.71 amps network losses R+r 6.3+1.6

The next topic to explore is that of Thus, the coil loss is I2R = 121.5 watts, matching network losses. Of course, there and I* R = 478.5 watts delivered to the antenna. antenna bandwidth The last topic for this article is that of 4b HA : 69 FEET the bandwidth for the antenna examples -KD- la R ;52 OHMS WWW.RADiOSCAMATORUL.Hi2.ROgiven. For each of these examples the 7TlPE C network was designed to make the input L NETWORK impedance seen by the coax feedline to be 52 ohms for a vswr of 1.0:1 at an arbitrary frequency of 3.8 MHz. Another computer program was written which calculated the input impedance versus frequency for the same network and same height vertical. The previous program 10 20 30 40 50 60 70 furnished the changing antenna self im- WWW.GiURUMELE.Hi2.RODNTENNA HEIGHT (FEETI pedance versus frequency. The changing

fig. 3. Bandwidth of vertical antennas vs height. input impedance versus frequency was Bandwidth edges defined by frequencies at plotted on a Smith chart for 30-, 40-, 50- which vswr increases to 2.0: 1. and 60-foot verticals using one type of L- network; the 69-foot vertical using a is no network loss for cases not using a series C network; and the 70-foot vertical using a different type of L-network. matching network, and I will also assume Bandwidth was arbitrarily defined as that there are no losses in any of the being the difference between those fre- network capacitors. However, there are quencies having a vswr of 2.0:1. These coil losses, and these can be significant bandwidths are shown in fig. 3. As for matching networks for short vertical expected, the shorter antennas have a antennas. Assuming that the power out- smaller bandwidth. Use of this graph will put to the matching network is 600 help you to select an antenna height watts, and that the Q of the network coil is 200, coil losses are as shown in fig. 2. depending upon what bandwidth is ac- ceptable to you. On the basis of this graph you can select a height of vertical depending upon the amount of network loss that you are references willing to accept. 1. Jerry Sevick, W2FMI, "The W2FMl Ground- As an example of these calculations, Mounted Short Vertical," QST, March, 1973, consider a 30-foot vertical, where HA = page 13. 30 feet, R = 6.3 ohms, and XL = 320 2. Edward C. Jordan, "Electromagnetic Waves ohms. If there are no capacitor losses, the and Radiating Systems," Prentice-Hall, New York, 1950, chapter 11 (impedance). 600 watts delivered by the coax feedline 3. John R. Kraus,Antennas, McGraw-Hill, New to the network must be divided between York, 1950. the network coil and the antenna. There 4. Robert E. Leo, W7LR. "An Impedance- are earth losses too, but I will consider Matching Method," QST, December, 1968, page 24. these in a later article, and assume that 5. Robert E. Leo, W7LR. "How to Design they are zero now in order to examine L-Networks," ham radio, February, 1974, page network losses. The coil loss resistance, r, 26. is XLIQ, or 3201200 = 1.6 ohms. The ham radio

march 1974 37 WWW.RADiOSCAMATORUL.Hi2.RO

lowpass filters

the problem of unwanted harmonics. It is WWW.GiURUMELE.Hi2.ROa recognized fact that a lowpass filter is a necessity with this type of amplifier.1 Many of the broadband amplifier designs use push-pull circuitry, which may su- press the second harmonic by 50 dB, but the third harmonic is suppressed only 12 dB.* I have selected an elliptic function filter design that provides low insertion loss, low vswr and attenuation peaks at Complete low-power, the second and third harmonics. It is assumed that a linear amplifier will be lowpass filter designs used in the phone portion of the bands but adequate suppression is obtained for CW operation too. for 160, 80, 40, Several listings of normalized filter data have been printed and are quite 20, 15 and 10 meters simple to use.314 Unfortunately, these publications are seldom in the average amateur's library. The theoretical design has been compromised only slightly to allow use of standard mica capacitors (either compression molded or dipped) that can be purchased from Allied, Newark or other suppliers. Five-hundred- Semiconductors have finally found their volt capacitors will handle several hun- way into high-frequency linear . dred watts if the vswr of the antenna is Broadband, untuned amplifiers that were near unity and are a wise choice unless seldom practical with vacuum tubes have low power and miniaturization is con- become the best approach with semi- templated. The Micrometals toroidal conductors. Along with the advantages of cores listed are readily available from rapid QSY and circuit simplicity comes Amidon Associates.

38 march 1974 fig. 1. 160-meter lowpass filter. L1 is 26 turns num- ber-18 on Amidon T80-2 toroid (4.2 pH). L2WWW.RADiOSCAMATORUL.Hi2.RO is 23 turns number-18 on Ami- don T8O-2 toroid (3.13 pH). lnsertion loss is 0.1 dB over the 160-meter band.

WWW.GiURUMELE.Hi2.RO

fig. 2. 80-meter lowpass filter. ~1 is 18 turns num- ber-16 on an Amidon T80-2 toroid (1.9 pH). L2 is 16 turns number-16 on an Amidon T80-2 toroid (1.46 pH). lnsertion loss is 0.12 dB over the 80-meter band.

FREQUENCY (MHz)

fig. 3. 40-meter lowpass filter. L1 is 10 turns num- ber-16 on an Arnidon T80-6 toroid (0.57 p).L2 is 9 turns number-16 on an Amidon T8O-6 toroid (0.41 pH). lnsertion loss below 18 MHz is 0.1 7 dB. FREQUENCY f MHz)

march 1974 39 fig. 4. 20-meter lowpass filter. L1 is 10 turns num- WWW.RADiOSCAMATORUL.Hi2.ROber-16 on an Amidon T80-6 toroid (0.57 pH). L2 is 9 turns number-16 on an Amidon TBO-6 toroid (0.41 pH). insertion loss below 18 MHz is 0.17 dB.

FREQUENCY (MHz) 0

- lo WWW.GiURUMELE.Hi2.RO - -a7 % L 4 -"

2 -40 9 fig. 5. 15-meter lowpass eC w filter. L1 is 9 turns num- $- -50 ber-16 on an Amidon T80-6 toroid (0.41 pH). L2 is 8 turns number-16 on an b0 Amidon T80-6 toroid (0.27 p).lnsertion loss below 24 MHz is 0.25 dB. M 15 8J 25 33 FREWENCY I MHz) 0

- I0

-a,

-rn D - -30 v, 3 4) 2 fig. 6. 10-meter lowpass 0 F filter. Ll is 8 turns num- 5 -m ber-16 on an Amidon 2 T80-6 toroid (0.33 pH). L2 is 7 turns number-16 on an -60 Amidon T80-6 toroid (0.19 pH). lnsertion loss I 1 below 35 MHz is 0.3 dB. 10 20 32493 100 mJa, sa? Xm FREWENCY (MHz)

40 GZ/I march 1974 Bathtub cans from old oil-filled capaci- tors make good cases with BNC or RCA Phono connectors soldered in the ends. If you are going solid state those old 1000-volt, oil-filled capacitors won't be needed anymore, so salvage the cases. Designs and winding information are given for the top six amateur bands. The response curves were obtained by compu- ter analysis with actual testbench verifica- tion of the 80- and 40-meter filters (those NEW YAESU FT-101-B are the two bandsWWW.RADiOSCAMATORUL.Hi2.RO I'm now working). The still $649 filters perform well without tuning, but a little adjustment of the resonant frequen- cy will help assure 60-dB suppression of the second and third harmonics. There includes new 8-pole fil- are several ways to tune the toroidal ter, LED indicators on resonators.5 In all six filters inductor L1 will resonate at the third harmonic and the clarifier and external L2 will be resonated at the second har- vfo switch. monic. PleaseWWW.GiURUMELE.Hi2.RO join me in fighting air pollution. Keep the bands upstairs clean for the The selling dealer is respon- other operators! sible for warrenty and service

references on Yaesu equipment. We have 1. Timothy P. Hulick, W9MIJ. "A Medium- a factory trained Japanese ser- Power HF SSB CW Transmitter, Part 11," QST, vice technician for expert ser- June, 1973, page 37. 2. "TRW Application Note CT-113-71," TRW vice and quick return. Semiconductors, 14520 Aviation Blvd., Lawn- dale, California 90260. 3. Von R. Saal, Der Entwurf Von Filtern Mit Hilfe Des Kataloges Normierter Tiefpasse, Tele- FTDX-401 transceiver $599 funken, GMBH, West Germany. FL-2100 linear $339 4. Anatol I. Zverev, Handbook of Filter Synthe- sis, John Wiley &Sons, New York, 1970. FL-dx-400 transmitter $339 5. G. Kent Shubert. WAOJYK, "Tuning Toroi- dal Inductors," ham radio, April, 1972, page FR-dx-400SD receiver $399 24. ham radio Most items in stock

FT-101 and FTDX-401 shipping will be prepaid in continental U.S.A. on cash orders

No sales tax (except in Nevada) Trade-ins wanted

"That's Dave's bad habit!"

march 1974 41

WWW.RADiOSCAMATORUL.Hi2.RO WWW.GiURUMELE.Hi2.RO+ a simplified digital readout system The word instrumentation has a magic ring and is something every true amateur desires, but usually cost tempers that I* desire. Some years ago, while fighting to 111 .: .: read a Potter counter which used four columns of four lamps each, displaying a C Discussion of a new BCD format, I was sure there must be a a better way. As transistors mutated to X and unique system w integrated circuits and costs plummeted, a number glyph was developed that could revolutionize numeral concepts. As not of glyphs c- r everyone is interested in the historical al 2 development of numerals, suffice it to say #" which are that man has spent several thousand years " developing and changing his numeric glyphs. Now the age of the computer will ideally suited 0 co require another change if man and . machine are ever to communicate direct- for use C 0 ly. ",n E invention with IC logic U e Accepting the fact that digital equip- 2 ment will never be anything more than E 'Rad-Ex Syntactics, 1043 East Atchison Street, Pasadena. California 91 104

42 march 1974 off and on switches relegates them to applied to a door and window forming binary operation. Man must learn to use the OR and NOR gates. these bits of information in an efficient Master these concepts and their ramifi- manner. My own approach to this binary cations, and you will be able to follow age is to reform the old Potter readout any logic design. One ingredient you must lamps by arranging them in illuminated apply to all logic is that in the real world bars as follows: a finite time must be allowed for signals ------O --+I 4I 41 SIG IN WWW.RADiOSCAMATORUL.Hi2.RO-4 -B ,CC -D

Why? These bars are a direct output from the decade counter. What has been gained? A readily readable symbol, re- DCBA duced cost, simplified circuitry and more 00000 00011 reliability.* 00102 00113 logic WWW.GiURUMELE.Hi2.RO01004 To answer in more detail, some discus- 01015 sion of logic, counters and circuitry is 01106 01117 necessary. It helps to remember that any 10008 digital device is just a mass of electrical 10019 switches. It depends on your own insight 1 0 10 10 = Reset signal and knowledge to parallel or series them 0000

fig. 1. Theotetical divide-by- 10 ripple count- er.

to pass through each logic block. Believe me, this is important. Usually, logic cir- cuits end up in a counter, probably for display, or register, a group of binary bits which will be processed further. The device of most interest to the amateur is the ripple counter. Fig. 1 is the logic diagram for a ripple counter decade unit. This unit should go through the binary sequence shown in the accom- panying table and repeat. to produce your desired result. For in- The old problems of finite time and stance, the door and screen door are AND reality interfere and develop into a condi- gates. Both must be open for the fly to tion called critical race. Beware of these come in. The results can be negative, problems. It's been the downfall of many NAND, if somebody is waiting with the designs. fly swatter. The same analogy can be What happens is that the reset pulse has set all flip-flops to zero but in so doing, flip-flop B passes a trigger signal to *US. Patent No. 3,671,943. A copy may be flip-flop C and you find yourself with obtained from the Commissioner of Patents, Washington, D.C. 20231 (50 cents money binary 0100. Thus, you spend a few more order). hours devising lockout circuitry so this

march 1974 43 WWW.RADiOSCAMATORUL.Hi2.RO

INPUT BD 0 I A I I

R RESETS TO 1001 R: RESETS TO 0000

fig. 2. CommercialWWW.GiURUMELE.Hi2.RO decade counter. can't happen (see fig. 2, a commercial technical decade counter). Now that your counter Electronically, the basic counter is is designed, you will need an indicator to different and more simple than present communicate the binary number it holds. decade counters, has no critical race About 30 years ago Potter built one of the first counters which, with four neon RAD-EX RIPPLE COUNTER WITH BCD OUTPUT lamps per decade, displayed the state of each flip-flop. Each lamp was weighted 1, 2, 4 or 8 and you simply added the values, or, to be more precise, you learn- ed binary equivalents for Hindu-Arabic numbers. Engineers soon mastered the art of using gates. From then on it didn't take too much time to build decoding logic which could combine the counter outputs and light individual one-of-ten lamps such as the . Finally, the ten outputs were combined into a diode matrix to illuminate a 7-segment numeral (see fig. 3). Rad-Ex began a search for a readout display which could be connected direct- ly to a counter and would convey a feeling of quantity. The Rad-Ex numerals fit this concept perfectly and in surprising ways open up several interesting possibili- TO NEXl ties such as handwritten machine readable DEC4DE characters, and a new way to teach fig. 4. Rad-Ex System, decade counter to arithmetic. readout.

44 march 1974 RIPPLE COUNTER WITH BCD OUTPUl

I 2 4 TO NEXT DECADE PULSE INPUT ECADE NETWORK l

WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

fig. 3. Decade counter decoded to 7-segment readout.

paths, while almost doubling the counting binary 0000 is a true starting point where rate and automatically suppressing lead- no count exists. It is also a unique way of ing zeros. Fig. 4 shows the circuit; its suppressing leading zeros. Once the truth table is below: counter starts, binary 101 0 becomes the systems designated zero. (For many rea-

DCBA sons it is handy to have a binary designa- 0 0 0 0State Before tion for zero; for instance, on a punch Count Begins tape a blank space is ambiguous.) Elec- 0001 tronically, good things happen too. Cir- 0010 cuitwise, the first flip-flop is independent 0011 0100 and needs no clear signal when counting. 0 10 1 Thus critical races are eliminated, allow- 0110 ing the use of a simple 3-input NAND 0111 gate to reset the counter for each decade 1000 count. 1001 10 10 For readout purposes, with one excep- 10 1 1AND to Reset tion, the lamps are tied through lamp 0001 drivers directly to the flip-flops. The one exception is the case where binary 1000 At first the truth table seems to also illuminates the lamp associated with indicate two zeros, but the fact is that flip-flop C.

march 1974 45 WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

wum TENS

fig. 5. Twenty-four hour clock using Rad-Ex readouts. application As the transition from binary 1001 to The use of the Rad-Ex system can best 1010 occurs, a pulse passes to a divide- be illustrated in a 24-hour clock where by-6 counter. Again, the non-conven- mixed counting is necessary. Fig. 5 is the tional system works to the advantage of simplicity. The truth table shows how the logic diagram for the clock and should be Rad-Ex numbers zero through 5 are used as reference in the following se- energized. quence of operation: 60 Hz is fed to a one-shot multivibrator, U1, simply to CBA eliminate false triggering. The output 001 from U1 triggers a chain of 7493 flip- 010 flops U2, U6, U7, which are used as a 011 ripple counter to divide incoming pulses 100 by 3600 (1 110,0001,0000). 10 1 11 0 All that is required for this operation 1 1 1 AND to Resets B & C is to detect the four binary ones and use a 001 4-input gate, U5, to reset U6 and U7 (U2 is already at 0000). The resulting one- The 24-hour portion of the clock uses minute pulses are fed to the first decade the standard Rad-Ex decade counter plus counter which displays zero to 9 minutes. a counter to keep track of the hours.

46 march 1974 Essentially, the decade counter acts the A check of the cost of ICs for this unit same as the minute decade with the amounts to $9.85. ICs for a comparable exception that the suppressed leading clock designed to use 7-segment readouts zero feature may be observed. The binary cost about $14.00. A set of Rad-Ex numbers 10 (2) and 0100 (4) are com- readouts costs $4.75; the 7-segment read- bined in a NAND gate, U8, to reset both outs and four decode units cost about decade and modulo-4 counters to binary $15.00.

VERTICAL CHANNEL WWW.RADiOSCAMATORUL.Hi2.RO COUNTER

/

4 F/f ~WATIC% I ouTpur (OIIOJ SCAN 1 REGISTER OUrwT "ZERO' DE TECTlON

WWW.GiURUMELE.Hi2.ROAMPLIFIER COUNTER VTAL CHANNEL 1 0I fig. 6. Rad-Ex optical reader device.

(00) (0000). Thus, until the first hour is future reached only the minute display is illumi- As mentioned earlier, this is a symbol nated. that can be handwritten and machine The sharp eye may spot two NAND read. Fig. 6 is a block diagram showing a gates, part of U3A and U8B, which don't method of scanning the numeral to set up seem quite right. Here you must juggle a BCD character. The number is scanned your logic thinking for in the case of the horizontally to pick up ones and vertical- NAND gate, I say, "If both inputs A and ly to pick up fours. These outputs are B (A-B)are high, Y is low (Y)." combined in a shift register which on command transmits the BCD word. Hopefully, this article will inspire ex- perimenters, hobbyests, and professionals to become involved in the man-machine You may look at this in a differencway communication problem. At present, and say, "If A or B (A+B) is low, (A+B), there is a growing need for man to com- Y is high. municate through handwritten glyphs di- rectly to computers, with bank drafts and zip codes being prime examples. There is also need to simplify instrumentation so These two NAND gates are used in a that digital voltmeters, frequency count- NOR sense, U8B is used to clear the ers, etc. can talk more directly and less decade counter whenever the count of expensively to you. Rad-Ex Syntactics ten or 24 is present. Gate U3A is used to feels we have brought these goals closer allow a fast or semi-fast setting of the to realization. clock. ham radio

march 1974 47 taeprinter TELEPRINTER

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48 march 1974 More Details? CHECK-OFF Page 94 Now you can afford the best! NOW; Free-standing or guyed, Tri-Ex Towers stress quality. All towers are hot dipped Top-of-the-Line galvanized after fabrication for longer life. Each series is specifically engi- Tri-Ex Towers neered to HAM operator requirements. for HAM operators W Series dt basicWWW.RADiOSCAMATORUL.Hi2.RO prices! An aerodynamic tower designed to hold 9 square feet in a 50 mph wind. Six models at different heights. M W Series Self-supporting when attached at first section - will hold normal Tri-Band beam. Six models. WWW.GiURUMELE.Hi2.RO LM Series A 'W' brace motorized tower. Holds large antenna loads up to 70 feet high. Super buy. TM Series Features tubular construc- tion for really big antenna loads. Up to 100 feet. Free-standing, with motors to raise and lower. THD Series Very popular. Low Cost. Holds Tri-Band antennas. Eight models- all support 7 square feet of antenna at full height in 70 mph winds. Guyed.

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More Details? CHECK-OFF Page 94 march 1974 49 WWW.RADiOSCAMATORUL.Hi2.ROnew fets

simplify bias problem The circuit shown in fig. 1 is a typical bias problems fet biasing arrangement. The gate of the fet is held at ground potential (zero volts) by resistor, R,, and the voltage drop across the source resistor, R,, biases the WWW.GiURUMELE.Hi2.ROsource terminal to some voltage above The operating ground. Thus, the gate is biased negative with respect to the source. The value of the gate-to-source bias is equal to the characteristics of product of the drain current, I,, in mA, and the source resistor, R,, in kilohms. If several new o R, is 2000 ohms and lo is 1.5 mA, the ;ub voltage across R, is 3 volts. The gate is V1 thus biased 3 volts more negative than the field-effect transistor U) source. f Fig. 2 shows how drain current varies families simplify ; versus gate-to-source voltage for an fet =ID whose I,,, is20mA.Thisfetcouldbe proper biasing an MPF102, a 2N3819 or a U183. A .-% straight line is drawn through the origin which represents a source resistor, R,, having a resistance of 1000 ohms. Notice that a change of one volt along this line P

J Many circuits in the amateur literature $ specify the Motorola MPF102 fet. The Texas Instruments 2N3819 and the Sili- ,,,- conix U 183 have essentially identical data z V) sheets to that of the MPF102. The rn trouble with all three of these devices is 2 the 10-to-1 spread of I,,, (2-20 mA) =- which makes bias point and performance 2 somewhat unpredictable. IDS, is the 2 drain current when zero bias is applied between the gate and source terminals of 3 fig. 1. Typical field-effect transistor biasing the fet. 6 arrangement.

50 march 1974 results in a change in current of 1 mA, indicating a resistance of 1000 ohms. The point where the straight line intersects the curve gives the values of drain current and gate-to-source voltage. In this case the drain current is about 3.7 mA, and the gate-to-source voltage (drop across R,) is about 3.7 volts. Fig. 3 shows how the situation is changed if the fet is replaced by one having a value of IDsS equal to 2 mA.WWW.RADiOSCAMATORUL.Hi2.RO The drain current is now 0.48 rnA, and the gate-to-sourcevoltage is 0.48 volt. This shows that the drain current of an MPF102, 2N3819 or U183 -0 5 -10 may be anywhere from 0.48 mA to 3.7 GATE. TO-SOUKE (VOLTS J mA when a 1000-ohm source bias resistor is used. fig. 3. Typical fet drain current vs gate bias characteristic for IDSS = 2 mA.

But if a 10k resistor is used for RD, and a WWW.GiURUMELE.Hi2.RO2N3819 with lDss equal to 20 mA is plugged into the circuit, the drain current will try to be 3.7 mA, which would produce a 37 volt drop across RD. Ob- viously this is impossible with a 15-volt supply, so the fet simply saturates, and linear amplification is not possible. If, on the other hand, RD is chosen so that it has a 5-volt drop when the current through it is 3.7 mA (IDssequal to 20 mA), its value would be 0 -5 -10 5 volts GATE- TO- SOURCE f VOLE) R, = 3.7 = 1.35k ohms fig. 2. Typical fet drain current vs gate bias If this value of resistor is used with an fet characteristic tor loss = 20 mA.

With such a wide range of possible drain current, it is impossible to choose an efficient drain load that would be suitable for all fets of these types. As an example, suppose a 2N3819 is to be used in a resistance-coupled audio amplifier stage such as shown in fig. 4. Under no-signal conditions, it is desired that the dc drain voltage be 10 volts. This means there must be a 5-volt drop across the drain resistor, RD. If a 2N3819 is used which has an lDSSof 2 mA, the drain current will be 0.48 mA, and the value of RD should be

5 volts - fig. 4. Simple audio amplifier circuit using a R, =------10.4k ohms 0.48 mA 2N3819 fet.

march 1974 51 having an IDS, of 2 mA, the drop across it will be only (0.48 mA) (1.35k) = 0.65 volt The problems involved in biasing fets with large IDS, spreads should now be quite apparent. new fets give relief One way to get around this biasing problem is to takeWWW.RADiOSCAMATORUL.Hi2.RO a large number of fets and sort them into groups, each group having a relatively narrow I,,, range. Fortunately, manufacturers are now doing this. Texas lnstruments has taken the 2N3819 and broken it into five fet GATE TO SOURCE (KILTS) types, each of which has an I,,, spread fig. 5. Typical drain current vs gate bias of 2 to 1 or less. These fets, which have a characteristic for Texas Instruments 2N5953 different pin configuration than the fet. 2N3819 are listed in table 1. All of these ohms. The drain current could be said to table 1.WWW.GiURUMELE.Hi2.RO List of 2N3819-type fets with small be 0.9 mA, + 0.2 mA for all 2N5953 fets lDss spreads. used with a 1000-ohm source bias re- fet type ~DSS sistor. Fig. 6 shows a practical fet audio amplifier circuit using the 2N5953. Volt- age gain is typically around 10, and any 2N5953 used in this circuit will be reasonably well biased. The Motorola 2N5484 series, priced at fets are priced under a dollar in small about a dollar each, have I,,, spreads of quantities, and they should be available 5 to 1 and 2.5 to 1. from any of the larger electronic whole- fet type ~DSS salers which stock TI semiconductors. 2N5484 1-5 mA Fig. 5 shows how the drain current of 2N5485 4-10 mA a 2N5953 would be in the range of 0.7 to 2N5486 8-20 mA 1.I mA if its source bias resistor is 1000 This isn't as good as the TI 2N5949 series, but is considerably better than the MPF102 types. conclusion The newer fets, having lower I,,, spreads, allow the use of simple bias arrangements to arrive at reproducible circuits. The cost of these devices is not much higher than the older types having wide I,,, spreads. Thus, fets may be applied with greater ease to a wide variety of circuit applications, and the high input impedance of fets may be taken advan- tage of without the penalty of unpre- fig. 6. Audio amplifier circuit using a dictable bias conditions. 2N5953 fet. ham radio

52 march 1974 When you WWW.RADiOSCAMATORUL.Hi2.ROwant FM equipment, you shouldn't have to wait for special sales to get the most value for your dollar. At the FM Supermarket every day is a special day for value. Whether you want the ruggedness and reliability of used commercial radios or the convenience of such radios as Clegg, ICOM. Genave, SBE, or our own synthesized SPEC II, you get the most in value from "The FM People". Here is just a small listing of the low every-day prices on used Motorola radios. Compare for yourself and see what we mean. WWW.GiURUMELE.Hi2.RO

LOW BAND HIGH BAND 12 volt-trunkmount 12 volt-trunkmount MODEL DESCRIPTION PRICE MODEL DESCRIPTION PRICE FMTRBOD 30w. dynamotor S 30.00 FMTRUBOD 30w. dynamotor S 35.00 FMTR140D 60w, dynamotor 40.00 FMTRUI4OD 50w. dynamotor 45.00 FMTR4lV 12w, vibrator 25.00 U43GGT 30w, transistor 100.00 U41GGT 30w, transistor 100.00 U43HHT 30w, motrac 200.00 U5lGGT 50w, transistor 110.00 U53HHT 50w, motrac 225.00 U41HHT 30w, motrac ps 200.00 U63HHT BOW, motrac 250.00 USIHHT SOW, motrac ps 225.00 U73MHT 110w. motrac 300.00 U71HHT 100w. motrac ps 250.00 T71GJT loow, transistor 125.00 6/12 volt-trunkmount T33GGV low. vibrator ps 50.00 6/12 volt-trunkmount T43GGV 25w, vibrator ps 75.00 T41GGV 30w. vibrator ps 70.00 T43GAD 30w. dynamotor 35.00 T51GGD 60w, dynamotor 40.00 U53GKT 60w. transistor ps 125.00 T51GGV 60w, vibrator ps 75.00 T53GKD 60w. dynamotor ps 65.00 T5lAGD 60w, dynamotor 40.00 FMTRU41V low. vibrator ps 25.00

Motracs subject to availability.

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More Details? CHECK-OFF Page 94 march 1974 53 ents

WWW.RADiOSCAMATORUL.Hi2.ROfoot, but many old timers accuse me of using at least a kilowatt. It goes without saying that W4AEO's log periodic, while requiring some acreage, provides considerable gain and solves the parts and money problem. Due to W4AEO's article, a number of us in log-periodic antennas Nicosia are building other log periodics. We are discovering that the surface has Dear HR: only been barely scratched, and amateurs LastWWW.GiURUMELE.Hi2.RO December the Cyprus Govern- still have plenty of elbow room to in- ment issued me a ham ticket. Then I corporate their own innovations. began a mad scramble, looking for a Stan Whiternan, 564AO/WIMDZ source of commercial beam antennas. I Nicosia, Cyprus quickly found that all antennas cost at least double the retail prices in the United States. Considering the cost of a beam, reciprocating detector tower and rotator, it was very discour- aging. Next, I searched for material for Dear HR: building my own beam. Aluminum is I have received several letters regarding practically unobtainable here, and PVC my "reciprocating detector" article which tubing was out because the available appeared in the March, 1972, issue of material is too thin and flexible. ham radio. Transistor Q5 is part of the The log-periodic antenna article by reciprocating detector switch, but the W4AEO in the September, 1972, issue of questions are understandable due to the ham radio provided the answer. It was the lack of a dot to show a connection in the only antenna I could find parts for and schematic; resistors R4 and R5 should be the design had sufficient gain to consider joined with a dot where these two re- working the United States (as noted by sistors form a junction point at the input myself and others, most of the signals to the diode and the base of Q5. The from the States on 20 meters average diode is a 1N252. 20-dB less here than reported by stations Several readers have also asked where located in continental Europe). the selectivity curve is 500-Hz wide and Putting the log periodic together was what is its slope. The filter I used was much faster than I imagined, but a vswr designed to have its 500-kHz passband at of 4: 1 when fed with 50-ohm coax was a the 3-dB points on a slope which is not puzzle until a check with a noise bridge particularly steep for an inductive filter. indicated the input impedance was 200 Indeed, at 500 Hz, the L3 inductance is ohms. I wound a 4:l balun and maximum very loosely coupled to the other two vswr on 15 and 20 meters is now 1.2: 1. sections of the transformer. The bandpass On-the-air reports indicate at least &dB formula (f,/Qo) indicates that the band- gain. I'm running a Collins KWM-2 bare- pass of the filter is actually narrower than

54 march 1974 500 Hz - in fact, bandpass is closer to closely approximates the 7.348692 pro- 250 Hz. The 390-ohm resistor used in vided by the square root key on my series with one of the differential inputs calculator. loads the thing down so it is broader. If As another example, my calculator the bandpass is too narrow, poor lock-in gives the square root of 75 as 8.660254. range is experienced on a-m, and there is Using the Mechanic's Rule, first iteration very poor "presence" in the quality of ssb results in an answer of 8.6875; the second signals. If the bandpass is too wide, poor then becomes 8.6602965, and the third impulse rejection will result. the desired 8.660254 whose square is Stirling M. Olberg, WISNN 74.999999. These answers were obtained WWW.RADiOSCAMATORUL.Hi2.ROWaltham, Massachusetts using the very crude first estimate of 8. Fred R. Scalf, Jr., K4EID vhf fm in the Springfield, Virginia United Kingdom Dear HR: I would like to add a note to the short Dear HR: article on finding square roots which Fm channel operation in the United appeared in the September, 1973, issue of Kingdom is now going strong, thanks to ham radio. the imported black boxes and new regula- In that article K9DHD gave a pro- tions WWW.GiURUMELE.Hi2.ROpermitting 12.5-kHz deviation cedure for estimating the square root of (there are lots of 25-kHz mobile equipment any number. By a simple extension, around, made by Pye and Storno). We arbitrary roots of any number can be now have one repeater working north of determined with a little work and a London in Hertferdshire. The callsign is hand-held digital calcu!ator. To find the GB3PI with input at 145.15 MHz and nth root of any number P, estimate the output at 145.75 MHz (600-kHz spacing). root, Xo, and use the following formula This repeater just covers outer N. London. Our Radio Society of Great Britain now has at least five applications for where XI is the desired root. For the case repeaters, and our group, the UK FM of a square root, n = 2, this formula is the Group (Southern), hopes to be able to same as that presented by K9DHD. For a put a repeater in Hampshire (one of five). cube root, n = 3, and the formula is Coverage of this repeater should be from Southampton to the edge of southwest London. John Akam, G8BIH For example, to find the cube root of 30, Wooteys, Alton, Hants first estimate the cube root (about 3.1). Then finding square roots

Dear HR: The technique for computing square This is very close to the accepted, approx- roots described in the ham notebook by imate, cube root of 30, 3.1072. Of K9DHD in the September, 1973, issue course, the closer your initial estimate, can be extended to increased accuracy by the closer the answer will be to the exact carrying out further iterations. For value. With a little patience, this formula example, if one uses the first approxima- will do great service to anyone making tion of the square root of 54 obtained as use of it. the next estimate and recomputes, an Stephen R. Alpert, WIGGN answer of 7.348469 is obtained; this Auburn, Massachusetts

march 1974 55 tebook

market. S~ncethe old 1242' code 1s passe WWW.RADiOSCAMATORUL.Hi2.ROnow, these switches can be purchased for surplus thumbwheel one-tenth of their original cost. The time switch modification required to rework each switch amounts to 7 to 10 minutes, so one evening's work At this year's Rochester Hamfest I can yield all the switches necessary for a picked up at a bargain price an assembly two-frequency synthesizer. of thumbwheel switches made for Fair- These switches can be identified by child consisting of 20 Digiswitch C units. placing a single unit so the thumbwheel I needed these to complete my frequency number is right side up and facing to the synthesizer.1 I took a chance on these switchesWWW.GiURUMELE.Hi2.RO in spite of the fact that the connector terminals plainly showed they were coded 1 2 4 2' (the last number is read, "two prime") and not the 1 2 4 8 BCD called for in most synthesizers. I took this calculated risk since, first, I am a cheapskate and the price was too good to resist, and second, I hoped to convert fig. 2. On the reverse side of the switch remove the switching to the required coding. the sections indicated and install the three I am happy to say that I was successful jumpers. in converting the switches to the desired right. The edge connector coming out the coding, and I offer the following for back then indicates, from bottom to top, other bargain hunters since these switches 335-1, which I presume is the model appear to be in plentiful supply and will number, C (common), and 1 2 4 2'. To probably be showing up on the surplus modify the switch, remove the PC board from the case and set it on the bench so the inside is facing upwards, and the gap is oriented at 9 or 10 o'clock. Using an Xacto knife, remove a thin sliver of the conducting material from the second and third contacts from the center as shown in fig. 1. The cut edges should be bevelled so the moving contact can slide up and over easily. At the same time, remove the 2' designation and scratch in an 8 in its place. Turn the PC board over and, referring to fig. 2, cut away all the conducting material indicated by the fig. 1. First step in the modification is removal crosshatch. From a small length of ap- of two thin sections of conducting material on proximately no. 22 stranded wire use a the wiper side of the switch. single strand to solder in the three jump-

56 a march 1974 ers where shown. Be sure the solder finding the doesn't lump up since these switches have minimal clearance between units when focal length of stacked. For best results use a small surplus soldering iron. dish antennas table 1. With an ohmmeter connected between The focal length of most parabolic the common and pins 1.2.4and 8, respectively. dish antennas can be determined with of the modified Digiswitch, you should obtain the following readings. two simple measurements, the diameter number 1 2 4 8 and the depth as shown in fig. 3. The 0 open WWW.RADiOSCAMATORUL.Hi2.ROopen open open antenna's surface can be described by 1 short open open open YZ = 4Px 2 open short open open 3 short short open open where P represents the distance from the 4 open open short open vertex to the focal point. The equation is 5 short open short open 6 open short short open that of a parabola with its vertex at x = 0, 7 short short short open Y = 0. The curve is symmetric about the 8 open open open short x-axis and opens to the plus-x direction. 9 short open open short The coordinates of one point other than the vertex are needed to determine the WhenWWW.GiURUMELE.Hi2.RO you are finished, put the two parts together and check out the switch- 11 Art5 ing sequence to make sure it agrees with table 1. Use an ohmmeter, one lead on C and the other lead on 1 2 4 and 8, respectively, to make sure the BCD se- quence is correct. Geo. Hrischenko, VE3DGX

reference 1. A.D. Helfrick, KZBLA, "High-Frequency Frequency Synthesizer," ham radio, October, 1972, page 16. fig. 3. Cross-section of a typical microwave dish antenna. Eguation for finding the focal point is given in the text. cutting a minibox curve. The edge of the antenna is a down to size convenient point. The diameter is equal Although several sizes of metal boxes to 2Y and the depth is equal to x. Solving and chassis are available to experimenters, for the focal length P sometimes the nearest size for your pro- ( diameter 12 ject is a little too large. It is not difficult P=- YZ-- 2 to reduce the height of a two-piece metal 4x 4 (depth) box. One-half of the box is the top and two ends; the other half is the bottom 1 (diameter)' and two sides. or P=- 16 depth From the first piece cut down the ends to the desired height. On the other piece The units of P are the same as those used cut down the sides to the same height. to measure the depth and diameter. This The result is a Minibox that fits and looks method also works for orange-peel or as good as the original, but which has segment dishes, but cannot be applied less height. directly to off-center-feed dish antennas. I. Queen, WPOUX John M. Franke, WA4WDL

march 1974 57 output in both the ssb and a-m mode, separately adjustable receiver incremental tuning and an external speaker connec- tion. The transceiver comes equipped WWW.RADiOSCAMATORUL.Hi2.ROwith push-tetalk dynamic microphone and mobile mounting bracket. For further information regarding the new SBE SB-50 6-meter transceiver, write to Linear Systems, Inc., 220 Airport Boulevard, Watsonville, California 95076, or use check-off on page 94. two-meter converter WWW.GiURUMELE.Hi2.ROJanel Labs has announced a new crystal-controlled two-meter converter six-meter transceiver that combines an impressive list of per- formance features with a low selling price. This new converter, the 144CC. rounds out the Janel line that already includes the deluxe 144CA high per- formance two-meter converter. Other products include converters for 50, 220 and 432 MHz as well as a complete line of receiving preamps. The new 144-MHz converter uses Linear Systems has announced the gate-protected dual-gate mosfets to pro- introduction of a new amateur transceiver vide high sensitivity while avoiding seri- for use on the 6-meter band. The trans- ous overload effects. The carefully design- ceiver, known as the SB-50, is com- ed circuit allows full utilization of the pletely solid-state and weighs only 7 mosfet sensitivity with one rf amplifier. pounds. The SB-50 is synthesized with This is of great help in preventing cross- variable frequency control of both re- modulation overload by keeping the sig- ceiver and transmitter with separate re- nal level low at the mixer. It allows ceiver incremental tuning control. It reception of signals with 15 to 20 dB covers the band from 50.05 to 50.28 greater strength than is possible for con- MHz. The new transceiver should be verters wtih two rf stages. especially useful for mobile installations The converter is virtually free from since it contains a very effective noise birdies due to the use of a seventh limiter. overtone crystal oscillator. This high over- The SB-50 is rated at 20-watts PEP tone oscillator eliminates the need for input and Swatts a-m. Receiver sensi- frequency multipliers. This feature, stan- tivity is less than 0.5 microvolt for 10-dB dard in all Janel converters, is very S + N/N and selectivity of 20 dB at 3 kHz effective in reducing suprious responses. and 60 dB at 6 kHz. Additional features Three tuned circuits between the rf am- include a lighted S-meter which indicates plifier and the mixer complete the de receive signal strength as well as power fense against spurious responses.

58 march 1974 More Details? CHECK-OFF Page 94 An attractive, metallic green, die-cast cabinet is used with this compact con- verter. BNC connectors are provided on the back panel for input and output. A power connector for 12 Vdc is also provided. Gain is 20 dB and noise figure is 3 to 5 dB. Converters are available for i-f frequencies of 26-30 MHz or 28-32 MHz. The units, completely guaranteed, are priced at an economical $49.95, postpaid. Order fromWWW.RADiOSCAMATORUL.Hi2.RO Janel Laboratories, Box 112, Succasunna, New Jersey 07876. For more information, use check-off on page 94. general-purpose op-amps

Mobile Antennas should be judged on the WWW.GiURUMELE.Hi2.RObasis of ruggedness, ease of installation and performance . . . mostly performance. Larsen Kirlrod Antennas are "solid" on all scores. They have a low, low silhouette for best appearance and minimum wind drag. Hi-impact epoxy base construction assures rugged long life. The Larsen mount gives you metal to metal contact, has only 3 simple parts and goes on fast and easily. And performance! Larsen Antennas for the 144-148 MHz range deliver a full 3 db Teledyne Semiconductor has intre gain over a 114 wave whip. V.S.W.R. is less than 1.3 to 1. The exclustve Larsen Kulrod duced a low cost, general purpose opera- assures you no loss of RF through heat. tional amplifier series, LM 141/142, Handles full 150 watts. It all adds up to superior performance.. which fills the performance gap between just one of many reasons why Larsen An- the 74 1 and 108 type op amps. l mproved tennas are the fastest growing line in the electrical characteristics of the new series include an increased slew -rate of 2V/ps providing full output voltage swing through the audio frequency range and reduced input bias current of 30 mA maximum and 5 mA input offset current maximum. Need a BETTER 450 MHz Antenna? The LM 141 series is fully mmpen- Get the Larsen 5 db gain Phased Collinear. Same rugged construction and reliability sated internally and is compatible with as the 2 meter Larsen Antennas including existing circuit designs using the popular exclusive Kilrod. Write for full fact sheet. 741, 107 and 1556. The uncompensated LM 142 series is a replacement for 101A, 748 and 777 applications and approaches the input performance of the 108 series amplifiers at a significant price reduction. 1161 N.E. 50th Ave. *Vancouver, WA 98665 The LM 141/142 is expected to fit applications where the 741 falls short on speed and impedance performance. They have excellent characteristics for sample

More Details? CHECK-OFF Page 94 march 1974 59 HERE IS A FIST FULL and hold circuits, long interval inte- graters, timers and active filter through of 2 METER POWER the audio frequency range. Each amplifier meets all of the standard electrical char- \ acteristics and also includes the con- venience features of short circuits and latch up protection found in other general-purpose amplifiers. Teledyne Semiconductor will provide a free sample of the LM 1411142 to WWW.RADiOSCAMATORUL.Hi2.ROqualified engineers who respond on com- pany letterhead with information on intended application. For more informa- tion, write to Teledyne Semiconductor, 1300 Terra Bella Avenue, Mountain View, California 94040, or use check-off on page 94. Mode! HRT-2 base-station power supply 5 Channel,WWW.GiURUMELE.Hi2.RO Narrow Band 2.2 watt FM Transceiver This light weight, "take anywhere" transceiver has the "Regency-type" interior componentery to give you what others are looking for in portable communications. You get a heavyweight 2.2 watt signal . . . or if you want, flip the HI/LO switch to 1 watt and the receiver gives you 0.7 uv sensitivity and 0.5 watts audio. Both transmitter and receiver employ band-pass circuitry so that power and sensitivity are maintained across the entire band. Get one to go. . . . only $17N00 Amateur Net E&L lnstruments has developed a new power supply designed primarily for ham -~y~YELEcmoNas. INc. radio enthusiasts. The unit, called the 7707 Records Street PW-4, produces enough power to operate Indianapolis, Indiana 46226 both an fm transceiver and an amplifier An FM Model For Every Purpose . . . simultaneously. The new PW-4 uses 110-120 volt ac input power, and pro- Everv Purse duces a rated output of 13 volts dc at 10 amps, IC regulated to +3%.This increased power capability means that amateurs HR.2MS HA-212 AR-2 with mobile units in their cars may take 8 Channel Transcan 12 Channel-20 Walt 2 Meter FM 2 Meter FM Transcaiver 2 Msrer FM Transcetvsr Power Ampllflsr them into homes for use at night. The

60 march 1974 More Details? CHECK-OFF Page 94 PW-4 features a modern cabinet design, current limiting and reliable heavyduty -~Z&C~HR-~Bgives components. It can be used with most 12 to 13volt a lot to talk over dc transceivers, together with 50 to 60watt amplifiers. The PW-4 is available direct from the factory, or from local distributors, at $84.95. For more informa- tion contact E&L Instruments, Inc., 61 First Street, Derby, Connecticut 06418, or use check-off onWWW.RADiOSCAMATORUL.Hi2.RO page 94. programmable voltage regulator American Made Quality at Import Prrce

Full 12 Channel, 15 Watts WWW.GiURUMELE.Hi2.ROwith HI/LO power switch Here is everything you need, at a price you like, for excellent 2 meter FM performance. The 12 transmit channels have individual trimmer capacitors for optimum workability in point- A 100-watt hybrid silicon voltage regu- to-point repeater applications. lator capable of line regulation of 0.10 Operate on 15 watts (minimum) percent and load regulation of 0.15 per- or switch to 1 watt. 0.35 uv sensitivity cent has been introduced by Motorola. and 3 watts of audio output The new MPClOOO is a 10-ampere posi- make for pleasant, reliable listening. tive or negative series voltage regulator And the compact package is capable of operating with input voltages matched by its price. as high as 60-volts. Output voltage can be adjusted from 2 to 35-volts. $Z28O0 Output currents of 10-amperes are Amateur Net easily obtained from the MPC1000 with- out external pass transistors; however, circuits using external pass transistors can expand the capability of the regulator to handle currents in excess of 50-amperes. 7707 Records Street Current limiting protection also has been Indianapolis, Indiana 46226 built-in to protect the regulator from excessive surge currents. The price for the MPC1000 in a 9-pin, An FM Model For Every Purpose . . . metal TO-3 package is $14.95 in single Every Purse unit quantities. For more information contact the Technical Information Cen- ter, Motorola Inc., Semiconductor Pro- ducts Division, P.O. Box 20924, Phoenix, HA 6 HA 220 ACT 10 HllIU Arizona 85036, or use check-off on page 12 Channel 25 Watt 12 Channels 10 Walls 3 Band I0 Channel FM 94. 6 Meter FM lransce~rrr 220 MHz FM Trmrce~vrr Scanner Rcrr~vrr

More Details? CHECK-OFF Page 94 march 1974 61 slinky dipole antenna

NURMl ELECTRONIC SUPPLY The Slinky Dipole is a new Amateur 1 ,. ,.111111,.-. 11, 172? Donna Rod .Wat Palm Bs~h.Florid. 33Ull antenna which combines good perform- PHONE - 13051 686-8563 ance with practical size and the ability to erect or disassemble in a minimum time. It requires no matching network for low THE ' DO EVERYTHING" 2% AMP. 1MO VOLT DIODE vswr operation in 50shm systems, and Mi7c~itcrl.t I% calchmg up on Iha bscklql and we've gal tt~i,llrands can be installed indoors in an attic or 01 thr.nl br~ckm sock 10'$300 103 57510 crawl space with 25- and 70-feet of mEm 40673'sWWW.RADiOSCAMATORUL.Hi2.RO available length. THE MOST POPULAR DUAL GATE PROTECTED MOS FET around God lo over 4M MHZ We 001 m .md you qrl em lor The Slinky Dipole operates at 80, 40 only S'b6W and 20 meters and comes in kit form, RG - 174lU including a balun, center insulator, 50- WF WENT THROUGH M MILES OF IT LAST TIME1 feet of RG-581U coaxial feedline, a Wc at, outhor8zt.d t1. 1~1~181) ~rthlltomand new 5hlpmenls have come ~n lrom the Idr ton, S~III a 5M -1 wlth a lrlend and PL259 connector and a pair of specially save $$$It BELDEN NO 0216 1M IS4 95 - 500'1918 40 made Slinky helical spring conductors. RF POWCR TRANSISTORS Assembly of the antenna from the kit Wr dud 11 aqam All brmo nt.w w#!h \!;mdavd components takes about one-half hour, nl.$rktn@ and mon were msnulncturrrl thcs year /I malot menulacturrr haprwd has RF pow lhtre and the initial setup from the completed and we bought hts Inventory WWW.GiURUMELE.Hi2.ROkit to an operating antenna can be accom- 71(56R( 3watlro"t (350 2N8W 10 Wanr Out 600 XUS2 lS Walls Out 10W plished in another 30 to 60 minutes, INK91 2~ watm c.,t 1200 2- m wwt. 611 1201 INRHO 4 Watm 5m 7NRXU 90 W1111 0ul 15 LKJ depending on the particular installation. All are Slllcon NPN and power outpffl ralvng are pod to The performance of the antenna is as 175 MHZ Hurry1 Somo guantlt#es are 11mmxi DO,- good as that of a full-size dipole. The KEVSTONE PERF %~* BOAR0 s ++* power capacity of the antenna is 1000 &-~4600 watts CW (2000 watts PEP on ssb), and 8; 8; 10 GI- Epoxv f 600&4 Per1 Board 3 64 Thvck 6990 0 the vswr is typically less than 2.5:l over

UNCLAD I COPPFR i ! .i. 8 ,:I '..:,I the full 80175-meter band and less than No Sln Iln I Rln I No Slra lur I Pnce 4729 2~4% 4238 7 14'~ Sl 3 1.8:l over the full 40- and 20-meter Ur) 2x6 185 4n1 49.6 bands. 4732 17x6 The antenna is very versatile. As op- posed to normal dipole antennas which only operate at discrete lengths, the Slinky Dipole will perform for any avail- able length between 24' and 70' on 80175 meters, between 12' and 35' on 40 meters, and between 18' and 6' on 20

-4 No M(1 WIC meters. The antenna will also work in an UAT11111 W thhb mvnia TdC., m 1m apartment house, provided that the steel WIclm cwem I "msc" '.A 7." -. supports used in the construction are more than 150-feet apart for 75-meter operation (75-feet apart for 40-meter

~ - e.pn~- wav 10 (xjr, l~.n<..I IS .I..,""!"'..,,,,i ,, Ylllrl ,xn(,,,t*x> run SAVE COSTLY lOOLlNl> AND SrlilE CHI\R(,FS K*l

-- use check-off on page 94.

62 march 1974 More Details? CHECK-OFF Page 94 variable rf attenuator

WWW.RADiOSCAMATORUL.Hi2.RO

Singer Instrumentation's new variable rf attenuator operates from dc to 500 MHz with an attenuator range of 10 to 60 dB. It is particularly suitable for coupling between instruments, checking trans- mitter out-put and receiver system degra- dation. Power dissipation is 100 mW. In- put and output impedances are 50 ohms. Typical WWW.GiURUMELE.Hi2.ROaccuracy curves for each 10 dB of attenuation over the full frequency range RCA CMCT30 are provided. The unit is priced at $130 and is available from Singer Instrumenta- 2 Meters tion, 321 1 South LaCienega Boulevard, Transistorized power Los Angeles, California 90016. For more supply, partially transis- information, use check-off on page 94. torized receiver, 30 watts, eliminating 12 volt, fully narrow banded, complete with engine interference accessories. . . Engine interference has long been a major problem to amateur mobile oper- ators. This new book is concerned with less crystals and antenna solving this problem in a practical man- ner. It explains why modern engines create interference and discusses the parts RCA CMCTGO of the engine that contribute to the 2 Meters problem. Instructions are included on how to identify and isolate the specific Transistorized power components that generate noise. supply, partially transis- Com m ercial noise-suppression and torized receiver, 60 watts, shielding techniques are discussed, and 12 volt, fully narrow instructions are given for their installa- banded, complete with tion. Diagrams covering the most com- accessories. mon types of automobile ignition wiring . . have been included. Automatic noise lim- iters are also covered as are such other interference problems as instruments, less crystals and antenna wheels and tires, turn and stop signals, power-supply vibrators and antennas. 128 pages, softbound, H.50 from HR Books, Greenville, New Hampshire 03048.

More Details? CHECK-OFF Page 94 march 1974 63 short circuits Uses Standard 7447 Decoder- driver. Seven Segment Read- outs. All tested and guaran- teed. Specs included. Fit stan- capacitance meter dard 14 pin DIP socket. Full .335 inch high. Color, RED. In the circuit for the capacitance Less Decimal $2.00 ppd. With Decimal $2.25 ppd. meter on page 50, of the August, 1972, With Colon $2.50 ppd. issue there should be a 2200-ohm resistor Same unit only contains nu- meral 1 and plus and minus connected between the base of transistor stgn. $2.25 ppd. 01 and the -6 volt bus. GI Printed Circuit type bridge . motorola dispatcher conversion 200 v PIV @ 1.5 A 50c ea or 3 for $1.25WWW.RADiOSCAMATORUL.Hi2.RO Inquiries and parts orders for this 400 v PIV @ 1.5 A 60( ea or 3 for $1.75 popular Motorola conversion should now be sent to the author at his new address: 1 LED Pilot Lites. 1 Full 3/16 inch Dia. John Darjany, WBGHXU, 622 Pacific I 4 for $1.00 ood. Avenue, Long Beach, California 90802. 1 JUMBO Seven Segment Readouts. Full .770 inches high. RED. Uses 7447 Decoder-driver. Specs inciuded. With Decimal point. $5.00 ppd. vhf superregen receiver Same unit only numeral 1 and plus & minus sign. $5.00 ppd. In the July, 1973, issue, on page 23, A@%)NEW NEW NEW the schematic for the vhf regenerative 6 foot Koil-Cord with molded receiver should include a 0.01-pF capaci- WWW.GiURUMELE.Hi2.ROPL-55 pluf. V;ry nice. 7 c ach 3 for $2.00 ppd. tor between the wiper of the 5000-ohm gain control and the base terminal of the General Purpose Geranium Diodes. Similar to 1N34a etc. 16 for $1.00 ppd. first TIS97 transistor. All Cathode banded. 100 for $5.00 ppd. Full leads. 1000 for $40.00 ppd. continuous-phase audio-shift keyer NEW Transformer - American Made - Fully shield- In the continuous-phase audio-shift ed. 115 V Primary. Sec. - 24-0-24 @ 1 amp keyer published in the October, 1973, with tap at 6.3 volt for pilot li ht. Price - A low 92.90 each ppd. issue the 2N5033 field-effect transistors used at Q1 and 03 must be Fairci~ild's.It 400 Volt PIV at 25 Amp. Bridge Rectifier. has been found that 2N5033s from other $4.00 ea. or 3 for $10.00 ppd. manufacturers have a different "on" re- 1-' sistance and are not usable in this applica- 6.3 Volt 1 Amp Transformer. Fully Shielded $1.60 Each DD~. tion. NEW two-meter cavity filter JUST ARRIVED - Transformer. 115 VAC pri- mary, 18 volt. 5 amp ccs or 7 amp inter- mittent duty secondary $6.00 ea. ppd. The dimensions for the two-stage, vhf cavity filter shown in fig. 3 on page 25 of NEW NEW TRANSFORMER. 115 volt pri- the December, 1973, issue are incorrect. mary, 12 volt 1/2 amp second- Use the following corrected dimensions ary. $1.50 ppd. when building this filter.

TOROIDS - YOUR CHOICE - 88 mhy or 44 mhy - 5 for $2.50 ppd. I frequency (MHz) 144 220 DIGITAL CLOCK on a single chip, national type 5314. Complete with specs and circuit 17.0" 7.30" $12.00 ea. ppd. 15.0" 5.20" I 12.9" 4.00" SEND STAMP FOR BARGAIN LIST 3.0" 3.00" Pa. residents add 6% State sales tax 1.5" 3.00" I ALL ITEMS PPD. USA 1 0.375" 1.00" 2.1" 1.20" 1.063" 2.75" m. weinnhenleer 0.75" 0.75" v K 3DPJ Box 353. IRWIN, PA. 15642 -----.---see text------

64 march 1974 LIKE FM OR 3 c\N WWW.RADiOSCAMATORUL.Hi2.ROThen you'll love. Data Engineering's new catalog

Write for your free copy today! WWW.GiURUMELE.Hi2.RO

TOUCH TONE PADS More features than any other pad including built-in monitor speaker and latest PhaseLock loop circuitry. TTP-l Standard pad for portable transceiver mounting. TTP-2 Standard pad in attractive case for home or mobile use. TTP.3 Mini-pad in attractive case for home or mobile use. TTP-4 Mini-pad for portable transceiver mounting. TTP-1. 2. 3 6 4, Sh. wt. 1 lb...... $44.50 TTP-1K. 2K. 3K & 4K. Sh. wt. 1 lb...... $34.50

CRICKET 1 A popularly priced IC keyer with more features for your dollar. Cricket 1 is a small slze, solid state keyer designed for the beginner as well as the most ad- vanced operator. It provides the user with fatigue-free sending and ~tsclean, crlsp CW allows for easy copy- ing at all speeds. Turned on its side, the Cricket can be used as a straight key for manual keying. CRICKET 1 Sh. Wt. 3 lbs. $49.95

2-METER PREAMP Specially made for both OLD and NEW receivers. The smallest and most powerful preamp available. Pro- vides 20dB gain at 2.5 N.F. to bring in the weakest signals. Sh. wt. 4 or. $9.50 kR $12.50 wired

Please include sufficient postage for shipping.

(DATA -ENGINEERING INC. -iiiiii iml) Ravenswood Industrial Park, Springfield. Va. 22151 5554 Port Royal Road 703-321-7171 L

More Details? CHECK-OFF Page 94 march 1974 65 JII>T APPI\ rl , :.t.(!rl+fr ,III~V,~L~!T! 1)~:. 6 ~Y?.CIAPP~. if ~QLI MI;SED OUT or1 OUI' LAII oirrDIrtc, CIP TIII~ BEAUTIFUL, COMMERCIAL WWW.RADiOSCAMATORUL.Hi2.ROGRADE KEYBOARD, HERE'S YOUP CtlANCE TO GET ONE AT THIS NE .'! LO.'!TR PRICE. IDEAL FOR AlJTOMATlC MOPSE CODE KEYERS, COMPUTER CON5OLES. AND VIDEO DATA TERMINALS. f POM ri LEADING VIDEO TEPMINAL MANUFACTURER. :YELL MADE .'!ITH THE LOO} AND FEEL OF AN EXPENSIVE ELECTRIC TYPFVIRITER. SIXTY FIVE KEYS . SPACE BAR. ALL ALPHABET . 10 NUMERALS 7e CONTROLKEYS I LOCLING "SHIFT" KEY. DIODE MATRIX FOR ASCII IS EASILY CONVERTED TO USE AS MORSE OR TTY KEYER. ATTRACTIVE SLANTED TIER. TPI-COLOR I.EY SCHEME. PREVIOUSLY SOLD FOR 99.50, NO?'! - POSTPAID - ONLY 534.95 LOW PRICES ON POPULAR COMPONENTS TYPE 8038 VCO FUNCTION GE?JCMTOF. ~ilF'rPl0R TO THE POPULAR 566. SINE, SOUARE, TRIANGLE GENEVATOP. lJSEARLE FROM .001 HZ TO OVER WWW.GiURUMELE.Hi2.ROI I MHz. VOLTAGE CONTROL, IOOO to I. CAN BE USED V:ITH SINGLE OR & CONTROL. PERFECT FOR USE IN SIGNAL GENERATORS, iM GENEPATOP5 AND PHASE LOCKED LOOPS. W/FULL SPECS...... S5 75

NO'? AND SURPLUS ELECTRONIC COMPONENTS FOR THE PRO AND 5ERIOUS AMATEUR. AN ORDER OR 8c STAMP PUTS YOU

NEW FOR 74 ECM 5A FM Modulation Meter .Opm lC5W Mhr Only .Cmtalront~oll*d la latad a)r* $8500 ':,:;::;- T)1 E EASY WAfl matson No Books.To Read .?"b ,dm No Visual Gomm#cksTo .0111q pow* .nth A1wncllls Ovstrnct You Just Ltsten And Learn Eased on modern prycholopiwl techntques-Th~s course wtll take Phone or write ''Sk<1,'. W9HAK t 9.95 YOU beyond 13 w.p.m. tn LESS THAN HALF THE TIME! 10' corn~>leteonlormrt*cvr Dtal Album contains three 12" Ava~lable on magnetoc tap. 812 476-2121 LP's 2% hr. lnltr~~tl~n$9.95 - Cmene, $10.95 Ava,lahleby bm I ,,tar! otnlv ORDER INFO 5pnd rnw* or rnonry ordo lor 585 W nlur 51.25 lot handling lndlan~aresw!enlr &

66 march 1974 More Details? CHECK-OFF Page 94 7YAEsu VAESU YOUR ASSURANCE OF PERFORMANCE & QUALITY v Amateur Prlce Net Subject to Change A High Performance AUTO SCAN WWW.RADiOSCAMATORUL.Hi2.RO2 Meter Mobile or Fixed Station FT-2 Auto Transceiver with Built-in AC Supply.

TRANSMITTER RF Output: 10 watts (HI) or 1 watt (LOW) into 50-ohm load at 13.5 volts DC. Frequency Stability: L 0.001 O6 Crystal Multiplication: 8 tlrnes. Modulation:WWW.GiURUMELE.Hi2.RO F3 (phase modulation). I Deviation: Up to c15 kHz (factory adjusted at k7.5 kHz). Audio Response: -+ 1. -3 dB of 6 dB/octave pre-emphas~s characteristic from 300 to 2500 Hz. Spurious Emissions: 60 dB below carrler minimum. Tone Burst: Nornlnally one second at 1800 Hz (adjustable between 1300 and 3000 Hz). Price - $379.00 RECEIVER Price Subject To Change Type: Without Notice Double conversion superhe. terodyne (crystal controlled). Intermediate Frequencies: 10.7 MHz first IF; 455 kHz second IF. Frequency coverage 146-148 MHz. 8 channels, 3 simplex Sensitivity: channels furnished - 146.76. 146.82. 146.94 MHz. Scan 0.3 UV for 20 dB StN/N speed: 20/sec. Pr~oritychannel at 2 sec. intervals. even when ratio. locked on another channel. 4 ohm dynamic speaker. AC Selectivity: power supply built in. DC current recelve .53 amps. Trans- .. 15 kHz at 6 dB: k25 kHz rnlt .92 amps. Low power. 2.1 amps High power. Signal at 60 dB. strength and relative output meter on front panel. Discrlrnl. Audio Output: nator rneterlng available at accessory plug. Size 8% x 4% 2 watts at 10% distortion. x 11%. Weight: 9 Ibs. All plugs and cables furnished.

AOIRONOACK RADIO SUPPLY 518442,8350 HAMTRONICS 215.357-1400 185 Wst Main Street. Amsterdam. New York 12010 4033 B~ownsvtlleRd.. Trwon, Pennwlvans 19047 AMATEUR ELECTRONIC SUPPLY 4144424200 HARRISON RAOlO 516.293 1990 4828 W. Fond du Lac Ave.. M~lwaukce.WISC. 53216 20 Smllh Street. Farmingdale. LI. Nn. York 11735 AMATEUR ELECTRONIC SUPPLY 305 894 3238 HENRY RAOlO 213-212-0861 621 Commonwealth Avenue, Orlando. Flor~da32803 11240 W OlympL Blvd.. Lor Angels. Callf. 90064 ELECTRONIC EXCHANGE CO. 508 834 9000 JUCE ELECTRONICS 817.926 5221 608 Papworth. Metat~~e.Lou~s~ana 10005 3850 S. Freeway. Fort Worth. Texas 76110 FRECK RADIO SUPPLY 104-254.9551 OUEEN CITY ELECTRONICS. INC. 513.931 1511 38 81ltmore Avenue. Ashwille. North Carollna 28807 1583 McMakrn Ave.. C~nc~nnat~.Ohlo 45231 GRAHAM ELECTRONICS 317-634 8486 RACOM ELECTRONICS 206-255.6656 133 S Pennsylvanta St.. Indianapolis. lnd~ana46204 15051 S E 128lh St.. Renton. Washlnglu~~99055 HAM RADIO CENTER 314 993 6060 WEBSTER RAOIO 209 224 5111 8342 Oltve Blvd.. St. LOUIS.Minour~ 63132 2602 Arhlan. Ffano. Cal~forn~a91326 HAM RADIO OUTLET 41 5.342-5751 WILSON ELECTRONICS 702 451-5191 999 Howard Avenue. Burlinpame. Cal~forn~a94010 P 0 BOX 116. P~ttman.Nevada 89044 YAESU MUSEN USA INC. \ 7625 E. Rosecrans Avenue. Unit #29 yA~~Paramount, California 90723 Phone 213-633-4007

More Details? CHECK-OFF Page 94 march 1974 a 67 GATEWAY ELECTRONICS 8123 PAGE AVENUE ST. LOUIS, MISSOURI 63130 314-427-6116 When you want - COLLINS MECHANICAL FILTER - Round case - from R.390A - 2kHz. 4 kHz. 8 kHz or 16 an authoritative, kHz. 445 kHz center freq. $15.00 VACUUM VAR. COND. - JENNlNGS UXC 500 WWW.RADiOSCAMATORUL.Hi2.RO- 500 mmf 1.. 15 KV $35.00 TEKTRONIX 527 WAVEFORM MONITOR - Ex. up to date directory Cond. - less case $295.00 GEL-CELL RECHARGEABLE BATTERY - 6 volt. 1 Amp 1% x 2 x 2 $3:50 of licensed radio 0.1" PUNCHED BOARD - Standard spaclng for 1C's Phenolic - 4.5 x 5.125 - $1.49. 4.5 x 17 . $3.19, 6 x 17 . $4.19 amateurs Epoxy - 4.5x6.5 - $1.69. 4.5x8.5 - $2.10 4.5 x 17 - $3.83 Push In Term~nalsfor above boards - Package It's the of 100 terminals - $1.80 8 x 8%" SINGLE SIDED PHENOLIC PC BOARD 50c TRANSISTORS - 2N2219 NPN Sil - 50c- 2N2222 CALLBOOK NPN Sil - 50c. 2N2905 PNP - 50r. 2~5646Unl- junct . 70c. 2N3394 NPN SII - 20r. 2N3569 NPN Over WWW.GiURUMELE.Hi2.RO210,000 QTH's SII - 45r. 2N3567 NPN SII . 40c 2N3905 PNP SII - 30c. 2N4072 NPN Sil RF . 751. 2N4852 in the DX edition Unbjunct - 70~.MJE1093 Pwr Darlington . $2.25 DX CALLBOOK for 1974 - $5 Minimum Order. $8.95 Visit us when in St. Louis. Please include sufficient postage. f-- -&+,.* the latest ... lrmy FCC .111111 .I*OUSTRV .PROPIOITIO" -,<< /3 .CONTESTS - .DI A

i ISSUE*

AFTER ISSUE

<'

L AFTER ISSUE!

*24 Issues per year Over 285,000 QTH's nl !I

,I + I in the U.S. edition U.S. CALLBOOK for 1974 $9.95 A IOU,paw Instant ncwslcttsr In the mall . See your favorite dealer or Send today to when 81 happens not (Mail orders add 50C per CALLBOOK week. 1.t.r for postage and handling) 1 year $12.00 US, Canada & Mexico - 515.00 Worldwide F~~ RAOlO AMATEUR *"~EE II booklNc Bu&~~uE&tPaE. 925 ShmdDrive Lake Bluff. 111. 60044

68 march 1974 More Details? CHECK-OFF Page 94 CW or RTTY, whichever way you go, HAL HAS TOP QUALITY YOU CAN AFFORD!

WWW.RADiOSCAMATORUL.Hi2.RO

.... 0 - - TOP QUALITY RTTY.. .WITH THE HAL QUALITV.-.WITA THE HAL lSSO MAINLINE ST-6 TU. Only 7 HAL clrcult boards (drllled GI0 glass) for all featurer, plug-in IC sockets, and KEYER- easy Opera- custom Thordamon transformer for both supplies, 115, tlOn- Perfectly timed CW with optional 230 V. 50-60 Hz. Klt wlthout caMnat,only 5135.00. screened. automatic ID for sending call letters, punched caMnet with pre-drllled connector ralls, 535.00; great for DX and RITY. TTL circuitry, boards and complete manual, $19.50; wired and tested transistor swilchlng for grid block. units, only $280 00 (wlth AK-1, $320.00): cathode keying. Handsome rugged crackle caMnet wlth brushed alumi- WWW.GiURUMELE.Hi2.ROnum panel With ID, only 590 00, with- OTHER HAL PRODUCTS INCLUDE: out ID, 565.00 ID-1 Repeater ldentlfler (wlred clrcult board) S 75.00. . ID-1 (completely assembled In 1%" rack cablnet) HAL ARRL FM Tmsmllter KIt S 50.00° W3FFG SSN Converter Kit S 55.00. Malnllne ST-5 TV KIt S 50.00. Malnllne AK-1 AFSK KIt 5 27.50-

TOP QUALITY.. . WITH THE HAL MKB-1 MORSE KEYBOARD. As easy as typlng a letter-you get automatlc CW wlth varlable speed and welght, ~nternalaud~o osc~llator wlth volume and tone controls. In- ternal speaker, and audio output jack. Smooth operat~on.completely solid- state. TTL clrcultry uslng GI0 glass boards, regulated power suppl~es, and h~ghvoltage transistor swltch. Optlonal automatic ID available As-

NEW FROM HAL- TOP QUALITY TOP QUALITY. ..WITH THE HAL RKB-1 RVD-1002 RTTY VIDEO DISPLAY TTY KEYBOARD. Gives you typewrlter-easy op UNIT. Revolutlonary approach to amateur eratlon wlth automatlc letterlnumber shlfl at four RTTY . . . provided vlsual dlsplay of recelved speeds (60. 86. 75, and 100 WPM). Use wlth RVD-1002 RrrY signal from any TU, at four spsed. (60.66, vldeo dlsplay system, or Insert In loop of any tale- 75, and 100 WPM), uslng a N recdver modlfled prlnler. for fast and easy RlTY. Completely solid state. for vldeo monltorlng. Panasonlc solld-state TV TTL circuitry uslng GI0 glass boards, regulated power

lverl RKB-1 assembled, only $275.00..

More Details? CHECK-OFF Page 94 march 1974 69 1S141ScTHo.Y1Cs 1600 DECKER AVE. SAN MARTIN. CALIF - LR/I ,046 (408) 683 4240,842 7349 - VHF POWER AMPLIFIERS irquency IIII~YIR~IIIC Now naI P Nornwt.1 IUHzI Yodel 1-1 1-1 Amp* Proc. 144 PA7128 I I I ' 19 $ 44 '5 PAIOPOR 5 40 .I J 79 95 PAIOIIU 'I - IS 13 7 0 17" 95 PA' 7Jll I - 4 I1 80 14495 PA10 IAOR 5 - I<> 147 180 11',1'> PA10 IdOR 1% - 40 110 170 If095 PI\ 14,11 1 - 4 Id0 70 0 ?PO PA101 t 5 - 15 I1 440 P45 25L 4 - 8 5 0 PA7 10L 1 - 4 30 60 141 45 'Av~!labtl~lyto be announced WWW.RADiOSCAMATORUL.Hi2.RO DEALER INQUIRIES INVITED a - - AK-1 BOARD ONLY S 3 25 AK 1 KIT OF ELECTRONIC PARTS S 20 00 ST-5 BOARDS ONLY $ 5 25 ST.5 KIT OF ELECTRONIC PARTS $ 47 50 ST-5A BOARDS ONLY S 5 25 ST-5A KIT OF ELECTRONIC PARTS $ 54 00 ST-6 BOARDS ONLY (These are the 8 or8 lnal by W6FFC) $ k8 00 ST.6 KIT OF ELECTRONIC PARTS $128 50 MOD. KIT FOR UPDATING THE ST.5 TO THE ST5A $ 900 PEMCO 250 EIGHT DIGIT COUNTER WITH BUILT.INWWW.GiURUMELE.Hi2.RO PRE.SCALER AND POWER SUPPLY PEMCOSEMI KITMODEL 50A FREQUENCY COUNTER$165 00 SEMI-KIT $125 00 These are full assambled and tested boards only, you adz your own cabtnet, etc. Wr~te for detalls. You must supply the cablnet A C. cord, meter, switches, etc on all kt(< except wher; noted olherwtsc (All prlces are postage pa~d(we pay shlpplng). We w~lldo mort any prlnted c~rcuitboard for ind~vlduals or prototypes If requlred we will also do the layout of the boards All our boards are G-10 glass-epoxy solder plated and come drilled only. At present lime we can do only stngle s~dcd All component parts used In our klls are new manufacturers stock We Do Not Use Any Used or LOW PRICES Surplus Parts All lnqutrles are answered promptly ELECTRONICS ON POPULAR COMPONENTS I)EMCO MANUFACTURING IF FILTERS 42fl1RthSt.,S.E..Salem,Ore.97301,(503) 585-1202 . Monolythlc crystal f~ltersat 10.7 and 169 MHz . Ceram~cfilters at 455 kHz SEMICONDUCTORS . VHF power trans~storsby CTC.Varlan . J and MOS FETS A5 . Llnear ICs - AM/FM IF, Audlo PA . Elpolar - RF and AF popular types Amateur Television INDUCTORS . Molded chokes Magaz~ne . Co~lforms - w~thadjustable cores CAPACITORS Be ..en as well as heard . Popular var~abletypes

SUBSCRIPTIONS ONLY QUALITY COMPONENTS No seconds or surplus $2 A . so rrre . Name brands - fully guaranteed . Spec sheets on request PO 80. 6S92 Phmla P.nna 99938 GREAT PRICES . Price breaks at low quant~t~es . Prlces below large mall order houses

INDUSTRIAL AND GOVERNMENT WRITE FOR CATALOG 173 ELECTRONIC SURPLUS P111T8 L PIECES FOR SCHOOLS. !WOPS HAMS MKUlVlSTS AMTECH SEN0 FOR OUA LATEST ALL DIFFERENT P. 0. BOX 624, MARION, IOWA 52302 MOnrrnLv PICTURE CATALOQ. NOW! (319) 377-7927 or (319) 377-2638 1 L

70 march 1974 More Details? CHECK-OFF Page 94 1.. 1.. .available TODAY! TheWWW.RADiOSCAMATORUL.Hi2.RO exciting all new INOUE IC1230!

WWW.GiURUMELE.Hi2.RO

TAKE A SLICE OUT OF THE FUTURE ...... and put 67+ CHANNELS* of 2-meter FM pleasure in the palms of your hands.. .with the SUPER COMPACT (2.3" x 6.1" x 9.7") IC-230. Feature-wise . . . the IC-230 is fully synthesized (with the new exclusive "Phase Lock Loop System") . . . a// modular construction (servicing is a snap-in and out) . . . a receiver that is very sensitive and selective as to what it hears (better than 0.4UV / 20db), with unique lnoue helical filters to eliminate intermod . . . plus a super E filter mosfet front end, making copy a pleasure.

And not a crystal to buy with the exclusive "Phase Lock Loop System". (That's close to $650.00 worth of xtals!) - GRAB HOLD OF THE IC-230 AT YOUR LOCAL DEALER TODAY -

Distributed by: ICOM WEST, INC. ADIRONDACK ICOM EAST Otv ACS. Inc.

Bellwue. Wash. 98005 Arn

More Details? CHECK-OFF Page 94 march 1974 71

- 'I'It 818 OIEIVIElt an experience in relaxed operating enjoyment

Full coverage. SSBICW. SB-36-personalized station and-with half-a-thousand watts 8040-20-15-10 meter bands. p.e.p. input, a table-top powerhouse. But much more! Picture the 500W p.e.p. power input. precision, 6-digit counter that reads out your frequency as 6-digit frequency counter fast as you can spin the free-turning, counter-weighted tuning reads to 100 Hertz. WWW.RADiOSCAMATORUL.Hi2.ROknob. And see how RIT (Receiver Incremental Tuning) obsoletes Selectable USBILSBICW. older, zero-beat-only'transceiver operation-prevents leap- Receiver Incremental Tuning frogging. Push the RIT button-zero-in received sigs +7kHz- Double conversion receiver without effecting transmit frequency! Also, change sidebands with fractional UV sensitivity without beat note shift or retuning. It takes two 9MHz crystal Panel multi-meter: "S" units. lattice filters to do this job. SB-36 has 'em. plate MA. RF out. ALC.

8 51 transistors (6-MOSFETS). 32 diodes. 6 vacuum tubes. 1151230VAC supply, speaker. In matching assembly cabinet. WRITE FORWWW.GiURUMELE.Hi2.RO COMPLETE BROCHURE.

- 220 Airport Blvd., Watsonville. CA 95076 !------Columbia Pays Top $ $ S ! PRINTED CIRCUIT BOARDS We need these today - now! / 1 I for any amateur project in any i • SP-6001X Harnrnerlund Rcvrs amateur periodical. aI I I a 618T Collins Transceivers Published with artwork I P.S. We're also hungry for: Bend~x. Collins, I a professional start I I

I desperate! I j D. L. "Mac" McClaren, W8URX I COLUMBIA ELECTRONIC SALES, INC. Printed Circuit Service for the Amateur I Box 9266-C, No. Hollywood. CA. 91609 19721 Maplewood Are. Cleveland. Ohio 44135 Phone: (213) 764-9030 1 216-267-3263 I ((-) ((-) EAST COAST SERVICE CENTER OWERS &MASTS CZ series towers. cranks up, installs We also service all other popular makes. without guy . New lacing design Complete professionally staffed labor- creates greater strength. atory fully equipped for all aspects of Mini and Magna rotating masts. . . high maintenance and service. Graduate Engi- strength galvanized tubing, self support. ing crank-up. neer on duty. Custom Design services For complete details and prices please available. check vour local dealer or write PROFESSIONAL ELECTRONICS CO., INC. ( ,,ifit *OCkLfi 1710 JOAN AVE. EUDOWOOO BRANCH BALTIMORE, MD. 21204 301-661-2123 P.O. Box 115. Hanford. California 93230

72 march 1974 More Details? CHECK-OFF Page 94 INTERNATIONAL EX CRYSTAL & EX KITS OSCILLATOR RF MIXER RF AMPLIFIER POWER AMPLIFIER WWW.RADiOSCAMATORUL.Hi2.RO

3. PAX-1 TRANSISTOR WWW.GiURUMELE.Hi2.RORF POWER AMP

for the COMMERCIAL user ... INTERNATIONAL PRECISION RADIO CRYSTALS

International Crystals are available from 70 KHz to 160 MHz in a wide variety of holders. Crystals for use in military equipment can be suppl~edto meet specil~cationsMIL-C-3098E. INTERNAT1ONAL

(HA) lor "High Accuracy" Close tern- CRVBTAL MFG. CO, INC. perature tolerance requirements. ,O NO LC* .OK,* , ,TY 73Y02

More Details? CHECK-OFF Page 94 march 1974 73 - PCB KlTS - RTTY SPEED CONVERTER/Drilled PCB 5 & 11 VDC $40.00 DRILLED PCB ONLY 5 6.50 RTTY AFSK Gen. All Shifts & CW I.C. 9 VDC C 2ma $7.25 100 kHz XTAL CALIBRATOR Less Xtal9 VOC @ 2ma $5.25 POWER SUPPLY - 28 VOC @ 650 ma output 59.85 PREAMP MICROPHONE 26 dB Gain 9 VOC 62 Ima 5335 LIMITER PREAMP For Hrqh Z M~ke 9 VOC C lma 55.30 PRODUCT OETECTOR For Your Receiver 9 VOC @ lma $3.95 "5" METER KIT Lrrs lma Meter 6.3VAC 55.25 SWR METER. Strlpllne, Lesr 200ua Meter 53 25 WWV CONVERTER 3.5-4.0 MHz Output 9 VDC C 5ma 55.75 Rrqu~res6.6.5MHz Crystal 6 METER CONVERTER FET Front End 9 VDC C? 5ma 56.50 7-11 MHz Output Less 43 MHz Xtal CW KEYING MONIT~R,RF Keyed, Lers Spkr. 9 VDC C? 9ma 55.20 WWW.RADiOSCAMATORUL.Hi2.ROPOWER SUPPLY. 9 VDC Q 50ma Outpul IISVAC 55.35 6 METER CASCODE PREAMP 80 VOC @ 4.5ma 55.45 Wired & Tested Lesr 2 ea 6CW4 DRILLS #51 56 58 or 60 (each) S.50 Finrri ~ual;ty fir PCB's, Made in USA Three For $1.25 EXCEPT AS NOTED ABOVE ALL KITS ARE NEW 100% SOLID STATE. AND C'OME COMPLETE WITH ~ri qlve blq audio "punch". UNDRJLLEO G-10 PCB () AN0 PTT d VOX switchlnq. 3Lb ALL PCB MOUNTED COMPONENTS. KlTS ARE LESS . POWER SUPPLIES, CHASSIS, AND ENCLOSURE HARO- WARE. SEND SELF-ADDRESSED STAMPED ENVELOPE COAX CABLE WITH PLUGS FOR COMPLETE DATA SHEET- A'ND SCHEMATIC. SATISFACTION GUARANTEED. RETURN IN 30 DAYS FOR REFUND. ALL KlTS POSTPAID. INCLUDE 25c Add $1 ea. for pack- HANDLING CHARGE. WASHINGTON RESIDENTS ADD WWW.GiURUMELE.Hi2.ROInq and sh~ppinq. 5.3% SALES TAX. 0R.ord.r BOTH 6 incl- - ude 334. 95 payment with orders for pre- Martex Corporation paid shipment USA. 519 S. AUSTIN, SEATTLE. WASH. 98108

OIGITAL:THEORV,DESIGN , I CONSTRUCTION I I #16 stranded copper wire I I Insulated for cleaner, easy handling I I LOGIC I Pretuned and tested guaranteed resonance I I Avatlable 80 thru 10 mpters amateur radlo bands I I Clipr ~ncludedfor portable use allowirg same coax lo be : IVE WSLETTER " I used for dllferent arllennar (small coax only) I SAMPLE COPY $1 .OO 1 Cl10 - $6.95 C115 - $7.95 C120 - $9.95 1 LOGIC NEWSLETTER C140 - $12.95 CIBO - $17.95 I PO8 252 i RG-58/U & RG-59/U,avalIable at 512.95 per 100 feet. WALDWlCK.N.J.07463 I Infortnal~onavailable or order d~rect I I I I CATRONICS INTERNATIONAL I I I I P. 0. BOX 132. MIAMI, FLORIDA 33156 I ?------!

RMC. XTALS-HX~-!IOOO. Price 4995 Silk Scrrmed Panel. Net to Amateurs I8 \\'stts 011tp11t. Complete with Tubes Power Supply $9.95 SIX METER TRANSMITTER MOBILE TUBE COMPLIMENT FIXED STATION 6U8 Osc~llatorMultiplier fir 12AX7 Speech Arnpl~fler EMERGENCY 2E?h Final Arnpllfler AVIATION 6BQ5 Modulator ------EXCELTRONICS RESEARCH LABS MANUFACTURERS OF ELECTRONIC DEVICES 224-15 Linden Rlvcl. Cambria Heights, N. Y. 11411

74 march 1974 More Details? CHECK-OFF Page 94

-- WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

Super Brick FEATURES Operates with ANY .5-3.5W Rig We use a 2N6084 final Transistor (each Reverse Voltage Protected one rated 40 W Infinite VSWR) featuring Load VSWR Proof EMllTER BALLASTED construction and of Dashboard control 8vailable first Quality. $0 you can't burn them out Fully automatic operation on command in tuning or under any load mis-match: each 5 MHz Bandwidth, 140-150 MHz Transistor has been individually Hand tested Harmonics: At least 40 dB down at DYCOMM before shipment. Rx insertion loss less than .5 dB Typical assembly time is 5 hours. Kit is - 80 dB Spurious Outputs complete with full assembly procedure, in- cluding lay-out Photos, and Manual. Tune.up and alignment is easy and straight forward using a watt-meter, dummy load and VOM. Kit includes: 6' control wire. 6' power cables (fused), 4' RG174 to make intercon- nect cable. 2 PL 259 connectors.

SPECIFICATIONS: Frequency range: 140-150 MHz. Power out- put: 40 W MAX for MAX input of 3.5 W. Input/output 2: 50 ohms. Input VSWR 1:3:1 Max. Load VSWR: Infinite. Power required: 11-15 VDC @ 6 to 7A. Weight: 2 Lbs. Dirnen- sions: 3" x 5" x 6". Operating modes: CW/FM.

Prices: KIT $49.95; Wired and Tested $99.95. Residents of Florida add 4% sales tax, shipping (UPS where possible) included. For Airmail add 52.00. Foreign-add postage extra. All parts are guaranteed and if a defective part should be found it will be replaced free within 30 days of shipment. Quantities Limited. First come - First sewed: this offer ends May 10. 1974. Send check or money order to DY COMM 948 he, r,P. 0. BOX 10116, Riviera Beach. Florida. 33404.1305-844-1323)

More Details? CHECK-OFF Page 94 march 1974 75 NYE VIKING PHONE PATCH

Be a GOOD GUY1 Complete a phone patch for a fellow ham. (First, install a Nye Viking phone patch.) It's great for your ego, and you really can provide a useful service1

The Nye Viking Hybrid phone patch has sepa- a rate controls WWW.RADiOSCAMATORUL.Hi2.ROfor receive and transmit audio. The adjustable null control allows normal VOX operat~onwlth most connections. Installation is EASY1 Mount it vertically, or in- stall it in any associated enclosure using the removable front panel as a face plate. Measures 2" x 6" x 2-112" deep (plus mountlng feet and knobs.) From an original design by E. F. Johnson, man- ufactured by the Wm. M. Nye Company. WWW.GiURUMELE.Hi2.ROSuggested list price, $34.50 at leading dealers throughout the U.S.A. and Europe. WM. M. NYE COMPANY, INC. Bchd 1519 -130th N E , Bellevue, Wash~ngton98005

SUPER CRYSTAL All checkedUSED and TEST operating EQUIPMENT unless otherw~se noted. FOB Monroe Money back (less sh~pp~ng) THE NEW DELUXE DIGITAL Zdr 20260 Hz 5.1200 375 Boonton 2028 8;FGen AM-FM 54916 MHz 325 Boonton 202E - Later verslon of above 585 SYNTHESIZER !! moM '$ . 2pcQ5 3:: HP185A Scope w/186B amp sampling lgHz 335 HP330C Dlst anal 20 Hz 2OkHz lo. 225 HP524D.Freq Counter Baslc un~tIOHz-1OMHz 185 HP540B Trans osc for 524 to 12 4gHz 185 HP608D (TS510A/U) s~ggen. 10.420 MHz 450 Nenis Clark 1671 FM rcvr 175.260MHz 125 Polarad MSG34.Stg. Gen 4 2.11gHz cal~b attn. AM FM Pulse mod. 495 . , . " - . .* Polarad R uwave rcvr .4.84gHz w~thplug-~n AM. . ...-.--.-:' FM. CW. Pulse - less plug-ln 225 Polarad TSA Spec Anal 01 44gHz wtth plug an MFA-22 DUAL VERSION - less plug ln 125 Also Available MFA-2 SINGLE VERSION HP803A Imp Brldge 50-500MHz. 2-200 ohm 195 Sol~tron 700A SCR testerchecks , gate . Transmit and Receive Operation: All unlts volts current, leakage and holdlng 165 have both Stmplex and Repeater Modes Stoddart NMlOA (URM 6) RF lntens mtr 10- . Accurate Frequency Control: .0005% ac- 250 kHz. complete wlth acc. 630 curacy Stoddart NM20A (PRM 1) RF intens mtr 15. . Stable Low Drift Outputs: 20 Hz per degree 25MHz. complete wlth acc 655 C typlcal Stoddart NM57A RFI rntr. .375-lgHz. w/ acc. 985 . Full 2 Meter Band Coverage: 144.00 to 147.99 ~~k RM 15 DC ~p scope 265 MHz ~n lOKC steps Tek 181 T~memark generator 9 5 . Fast Acting Circu~t: 0.15 second typical set- ~,k 190~const ~~~l slg G~~ 35.50~~~175 tl~ngtlme Tek 531 DC 15MHz scope-takes letter plug-ln 175 . Low Impedance (50 ohm) Outputs: Allow long ~ek565 dual beam 10 MHz scope, less pluglns 625 cable runs for mobtles SG24/TRM3 Sweep Gen 15.400 MHz. CW. AM. . Low Spurlous Output Level: similar to crystal FM Xtal markers, scope-Dev to 20% 245 output TS 407A SIR Gen (HPGl6) 1 8-4gHz 385 SEND FOR URM 7 RI.FI mtr (slm NF-105) 20.400MHz 750 FREE DETAILS Electronics (Send SASE for complete Ilst) Pr~cesMFA-2 $210.00 BOX 1201H Electrontcs MFA-22 $275.00 CHAMPAIGN. ILL. GRAY P. 0.BOX 941. Monroe. MI 48161 Shipping $3 00 extra 61820 Spectallzlng In used test equipment

76 march 1974 More Details? CHECK-OFF Page 94 WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

More Details? CHECK-OFF Page 94 march 1974 77 I'

MODEL 60 SPEECH OR0 MODEL 20 DIGITAL DIAL :~.,\~l,~l>le10, t~~~.!v~~ia~~~~-l~~-~~ahral~',I, .:, vchwavr- ( ,llrl5 2n.l Drah~year il,it,n.~l ti,,#r d!q#l tt.rm as much as 8 db II . 8 I ,qar#thmlc 11.d1111111 ,tnd clyclal tlmt, 1, 15,- OSY your MODEL 11A PADDLE I)$,\~qnedwoth re- wncztile Oorrnles w!h f !.' Sc13 .~ntlAM 1111,ft or mrlbolp transm~tti~r16.i t,lvcr i!r trans- llahllltv ~n rn,,,! 11 tnechanm

TEN TEC-TRITON II $606.00 TEN TEC-TRITON I $519.00 MAGNUM 6 RF PROCESSORS MOR GAIN A GENAVE 2 MOSLEY.CLAS REGENCY HR- HYGAIN TH6D WWW.GiURUMELE.Hi2.ROGALAXY GT-55 VENUS SSTV GLADDING 25 $249.95 STANDARD 146A $289 00 LOU GOLDSTEIN, K4LAN P.O. BOX 3561. PENSACOLA. FLA. 32506 Drop me a I~nefor those unadvert~sedextras f fgn\ "11 'SKY-SLOT" ANTENNA (TV-FM) 11 d GLADE VALLEY SCHOOL RADIO SESSION l.5tl1 vcnr - 111111 27 - Atrc. 9. 197.: Courses Taught: General Theory and Code Advanced Theory and Code Amateur Extra Theory and Code Golf privileges at New River Country Club: also fishing I TRC'L1' A \'ACATlOlV \VITII A PURPOSE!!!

".5 .*-., .,. ..,%.." no Pr~rtl~lf,nttrndrd fn~tfrtlrc follo~cin~.states: \ 2 S~~rtii(:t~rol~fi;~, Sot~th (:~ln,lin;~. \fis\,u~ri, Tennes- sre, Llt;111. Floricl:~. Okli~h~~fiii~.\\'c~t \'ircini;~. ,\);I- hxnin, Kt,\\, llnmpshirt.. loaa. District t~f(:ol~tmliin, TV-FM-CLASS E CB ANTENNA NEW \'rnnont, Ariz~~nn,1ndi;lnn Ohill Sen- Jersey. ROLLABLE (with perfect color band.w~dth). Just New York. hlass;~~hnsc~lt.;.hiaryl;lnd. \.lrcini;i. Illi- unroll and stick on wall. Uses no masts. no nols h1irhic:ln. (.WI~CI:I. Kansas, >fissirsil, li Sr- rabbit ears, no dangerous plugging to AC lines. 1)r;Iska. ~li~irre~Krnt~~cky, ~:nIif<>rni;~, S~V \i:.xiro, Ark;~nsas. Texas. \\'isconsin. L~~r~isisrii~,Orrgg~n, and NO SIGNAL SPLITTERS slnce the VHF.UHF. (:onnt.rtir~~t. hlinnesr~t;~.Pennsyl\fani;~. FM terminals (VHF usable for CB with high \\'r've rhnngecl onr name and Ir~mtinn.\Vr have power handling) available at the same time. illst m<~vc.clfrjr~r milt-s frrrrn onr previf~nrsitr. \\'c (New 1971 slotted design with U.S. Patent ilrr no\v Ian th~CRIII~IIS 111 R henr~t~f~~lsrnall h~mrtl- S/N 3577196). Made of decorative foil/plastic ine srhru)l. llxcellcnt ;~rc~rmnr~,cI;~tions.sntnr co<~cI yet rugged for use in yatch or RV. Antenna fgwd ancl tlit- samv rxc~llrntinstr~~rt~~rs. size: 18" x 48" unrolled. works behind picture. I against metal! Price is only $15 for model with C. L. Peters K4DNJ Director I I following gain: (VHF . 9 dB), (UHF - 12 dB). P. 0. Box 7j0. Elkin: North Carolina 28621 (FM - 6 dB); gains above dipole. I Plmsr acrid mr tl~rRooklrt nnd A,,),licrrtic~n Rlnnk : I for thr (:lrrdr \'nllvy Scl~ooIRntfin Sc..ssion. I Order postpaid AIRMAIL, insured, from ANTENNA DESIGN CO. I j Address I 11621 HUGHES AVE., N.E. 1 - I ALBUQUERQUE, N. M. 87112

78 march 1974 More Details? CHECK-OFF Page 94 I INTERNATIONAL ELECTRONICS UNLIMITED I

WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

,104 2Yrn"YIOS,rnII I1mr 0 802. *t RAM- 19s- INTERNATIONAL ELECTRONICS UNLIMITED ,024 t., RAM *$ P" - Lapl-uwla .mr P.O. BOX 1708R IUI ULn(lU7TL I=" em -.-Rw LS.. Montermy, Calif. 93940 4 A

More Details? CHECK-OFF Page 94 march 1974 79 PUNCHED TAPE EQUIPMENT DUAL BAND ANTENNAS Burrows A522 or A560 Tape Perforator. 8-unit Tllr~rrr;~dv ((1 rn,,tlrlt flntc.nnas t.~,n\iht (11 111ll code on I-lnch tape. Used, exc. cond. Shpg. wt. '2 \vi~vl.Ivnhth clrmr.nts of 51,. 12 ct,l,pc.r\\.c.ld 35 Ibs. $75.00 wire nncl r;ln llr ~~st'tlns eith~rdipo11.s or in- Friden Model 8A or 8C tape perforator and vertrd v1.e~. SGBtrill>\, coils, ci~t~nl~ck%.cstc. ;ire reader In one unit. 8-unit code on 1" tape. nsecl tc~ shnrtm the rl~ri~ent~.%\\' riltinc. Used, exc. cond. Shpg. wt. 100 Ibs. $150.00 Sirlrlr NI;IX feedline rt~rl~~tr~.cl.Incli\~icl~~.~ll~ n11111nte11cli~x~les w~th C~BII~~II~~ rt*ntt,r nns111;1t,>r: Teletype Model 28 tape unit. Tape reader LBXD 80/40, $21.!)5; 40/20, $16.25; 201 1.5, S 14.1 0. 3.speeds, 60-75-100 WPM; H'igh-speed perforate; BRPE 700 WPM on LRXB9 Base all mounted 0thr.r c~,llihin;~lir,ns av;~il:thlc.. Scntl f,,r free c:~t:tlttt! listinc CIII~IIhi~ncl. !IIIBIIII~~;I~~. and Ia~l11- on L~HSTape H'andling unlt. EXC.' cond.. as re. ell clil~t~lc*:III~I-I~II:IS. 13i1111ns :~v;~ili~l>le.1'ostp;kicI moved from service. S~DP.- wt. 100 Ibs rontc.nnin:~l C'. S. A. %7

80 march 1974 More Details? CHECK-OFF Page 94 WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

CHANNELS

I .5 uv for 20 dB quieting I I aluminum case 2% x 11/2 x 9 I dual conversion I prewound coils I I ceramic 455 filter predrilled PC boards I I silk screened parts layout for easy construction I ORDER YOURS NOW

Please send me - HT-144 (r $99 95 each

Name------Total ------

Address ------Sh~pp~ng($1 00/klt) -

CltY ------NYS res sales tax State - - ZIP- - --TOTAL ENCLOSED ------.

- - DIV. OF BROWNIAN ELECT. CORP. - n320 WATER ST. POB 1921 BINGHAMTON, N.Y. 13902 607-723-9574

More Details? CHECK-OFF Page 94 march 1974 81 COMPUTER KEY BOARD 313,344 CORE MEMORY $125.00 From SPECTRA computer. vlsually OK. 64 x $7.00 (as is) 68 x 4 x 18 core stack. Flgures out to 35K Byte. - - T :,-7 LED 7 LIJCltL1 C.+bCk+ ; SEGMENT READOUT -~c'@c~ccctttt Similar to MAN.1. Factory sec- r,C,C#CbbbLCC Y onds but functionally OK. Fit 14 pin DIP socket. dLwLLLLLkh.I 7 segment w/left decimal L- *LED-A-L $3.00 -- 7 segment w/right decimal ! +LED-A-R 3.25 -.r--wuA 7 segment no decimal r LED-A 2.75 Above LEDS 2 for the price of 1 Several styles on handWWW.RADiOSCAMATORUL.Hi2.RO in poor condition, broken Socket for above, gold plated key/keys, broken case or no case, etc. Still a leads 3/1.00 good value at $7.00 for parts. switches. and each has encoder board in base. IC SALE YOUR CHOICE 3 for $1.00 2N2152 45 volt 170 watt PNP.G pl 900 BUFFER TO.5 '2N3713 80 170 NPN-S 1.00 111 914 DUAL 2 INPUT GATE TO-5 *2N3789 60 150 PNP-S .75 jil 923 JK FLIP FLOP TO-5 2N5301 40 200 NPN-S 1.25 pl 926 HI speed JK FLIP FLOP T0.5 '2N5301 40 200 NPN-S 1.00 111 931 JK/RS FLIP FLOP (DIP) *Removed from used equipment 10 pin socket for T0.5 IC 3/1.00

TRANSFORMERS 'l.OO GIANT NIXIE B7971Brand New 32.00 BRAND NEW. 115 volt AC Input. OP . AMP With for 'IANT 'lock' XFMR, out puts: 16 VCT I/, amp, 17 VCT I/, amp. WWW.GiURUMELE.Hi2.RO$3.50 COMPUTER TAPE DECK $75.00 Takes I:. Inch tape. made by Computer Entry FILAMENT or BTRY CHARGER XFMR Systems. V~sually ok, wlth electrontcs, no data output of 18 volts at 4.5 amp $3.50 available. CALCULATOR PHONE PATCH KIT Includes all parts, instructions, cabinet. AM PATCH - $5.00 SSB PATCH - $9.00 CMOS 4814 HEX INVERTER

for $ 15.00.

CT 5005 Dual DUAL16 bit memory, 16 BITserial MEMORYMOS by Philco T0.5 im case. brand new with 2 page specs. CALCULATOR CHIP YPLR 532 $1.00 each $10/12 Single MOS chip with all log~crequlred for 12 diglt 4 function desk top calculator with extra storage register for memory or constant. Mul. tiplexed 7 segment outputs for LED. Incan- 2048 BIT MOS MEMORY descent. Fluorescent, or Gas Discharge displays. 2048 bit MOS LSI random access memory NEC Brand new, bargain priced, with specs. 6003. All lnputs except clock are TTL com- $8.00 each. 2 for $15.00 patible. 2048 word by 1 bit. 22 pin ceramic dual-in-line. With specs. HP $9.00 each 2 for $17.00 RCA INJECTION LASER DIODES LED Another SUPER SCOOP by Meshna. Brand new RCA packaged, cons~deredobsolete by RCA but DISPLAYS ~~~is~~at~~O~~p~~~~~~!r~~\~~~~~1 ~~~d~~~ Brand new 4.0n.a.strip LEO readouts. End-butt two strips and come up with 8 digit readout. An unheard of Super Value . . . f8.00,per strip. 2 strlps 515.00 Another strip . . . this one a Clock Chip readout. 2 digits . . . a space . . and 2 more dlgits. Just right for a clock reading hours and min. Postage Extra on all Items utes. This one only $8.00 JOHN MESHNA JR. ELECTRONICS P. 0. Box 62 E. Lynn, Mass. 01904

82 march 1974 More Details? CHECK-OFF Page 94 WORLD QSL - See ad- page 84. HAMFEST! Indiana's friendliest and largest spring hamfest. Wabash County ARC'S 6th Annual Ham- fest. May 19 1974 4-H fairgrounds raln or shone. Admission siill on'ly $1.00 for advanced, tickets ($1.50 at gate). Large flea market, techntcal ses- sions bingo for XYL's, free overnight camping. flea ~t plent; of parking. Bonus for car-pools (4 or more adults per car). For more informat~onor advanced tickets wrote: Jerry Clevenger, WA9ZHU. Route 4. market Wabash, Indiana 46992. FRAME & DISPLAY your QSL's with 20 pocket plas. tic holders. Two for $1.00, seven for $3.00 from your dealer or dorect, prepa~d. Free sample to dealers upon request. TEPABCO. Box 198H. Galla. tin. Tennessee 37077. SURPLUS TEST EQUIPMENT. VHF and microwave I RATES CommercialWWW.RADiOSCAMATORUL.Hi2.RO Ads 35$ per gear; wrlte for bulletins. Dav~d Edsall. 2843 St. word; non-commercial ads lo$ per word Paul. Baltimore. Md. -21218. payable in advance. No cash discounts CANTON AMATEUR RADIO CLUB annual auction & flea market, Friday. March 8, 1974. at the Imperial or agency commissions allowed. House Motel in Canton. Ohio. at 730 p.m. Doors open for set-up at 500 p.m., mobile check-ins on I COPY No special layout or arrange- 147.06 & 146.94 Simplex, Stark County, repeater ments available. Material should be type- 146.19/79. Grand Proze. moblle check-~n prlze, other prlzes awarded each half-hour. Free coffee written or clearly printed and must in- and donuts. All companies are invited to attend clude full name and address. We reserve and set up dis lays and exhibitions, free space will be provided: For reservations or information the right to reject unsuitable copy. Ham contact Mack Schontz, WBBNUA. 601 Perry Dr. N.W., Radio can not check out each advertiser Canton. Ohoo. and thus cannot be held responsible for DO-IT-URSELF DXPEDITION - Stay at ZFlSB - claims made. Liability for correctness of Cayman Is. Vertical antenna and Caribbean at your doorstep. Diving/fishing if band folds. We arrange materialWWW.GiURUMELE.Hi2.RO limited to corrected ad in next license. Write Spanish Bay Reef Resort. Box BOOK, available issue. Deadline is 15th of Grand Cayman, B. W. -I. second preceding month. SECOND ANNUAL WOODWARD HAMFEST-SWAP- FEST will be held on March 30.31, 1974. The event I SEND MATERIAL TO: Flea Market, will be held at the Woodward County fairbuildlng Ham Radio, Greenville, N. H. 03048. in Woodward, Okla. NEED PARTS? We carry parts for R.388-390-390A. 391.392-1051-5151 - Nems Clark-Racal-Pack sets - PRC-25-41-47-62-70-71-73-74-77.If you need a part 19TH ANNUAL HAMFEAST AND AUCTION to be held no matter what you have. If itsFU.S. government Saturday, March 9, 1974 at the Lucas County Rec. we have it or can get ot. Also we want to buy or Center 290 Key St. Maumee, Ohio. Registration trade all aircraft communications. All ground radio $2.00 'at door. $,1.50 advance. For further info. communications. All plug-in modules control heads. write Toledo Mob~leRad~o. Ass'n., P. 0. Box 273. No matter what cond. they are in - bent or busted Toledo, Ohio 43695. - ok. We will buy or trade. We have R-390-388-390A. RESISTORS: Carbon composit~on brand new. All 392-1051-51S1 Nems Clark - Racal - and new ham standard values stocked. '/zW 10% 40/$1.00; S$W gear for trade. D & R Electronics, R. D. #l. Box 10% 30/$1.00 - 10 resistors per value. please. 56. Milton, Pa. 17847. Phone 1-717-742-4604 after Minimum order $5.00. 15W RMS 1C Audio Ampll- 6:00 P.M. - fier - Panasonic. Frequency response 20Hz.100 kHz. L/, % distortion. Price $6.95 Postpaid. Pace NORTH ,FLORIDA SWAPFEST, March 31, 1974, Electronic Products. Box 161.H. Ontario Center. Comrnunlty Center. Hwy 98. Write: PARC. Box 873. New York 14520. - Fort Walton Beach, Fla. 32548. OUTSTANDING RlTY MANUAL. Teleprinter hand. book. Covers everything. Beautiful hardbound vol- QSLS. Second to none. Same day service. Samples ume. $14.95 ppd. from HR Books, Greenville, 25~.Ray. K7HLR. Box 331. Clearfield, Utah 84015. NH 03048. - - THE KNIGHT RAIDERS VHF CLUB'S auction and QRP STATION. Ten-Tec PM3A transceiver 210 PS flea market is Sunday, March 24 at the YM-YWHA AC5 , used 2 hours, $75.00 ostpaid ' of North Jersey. 152 Van Houten St.. Paterson. Cornils, 1293 West L. Benicia, Cal~f.$4510. Free admission free parking, refreshments avail- able. Talk.in 166.94 MHz. Flea market tables $5 for 8 ft. or $2.50 for '/2 table. Reserve tables In PRECISION HAND TOOLS, special harmexperimenter advance: Kni ht Raiders VHF Club. Inc., K2DEL, discount. Letter brings mailings. Artisan Tool Com- P. 0. Box 1024, Passa~c,-N. J. 07055. pany. Box 36. Glenmont. New York 12077. RECIPROCATING DETECTOR, write Peter Meacham WANT OLD RADIO SHOW TRANSCRIPTION discs. Associates, 19 Loretta Road, Waltham, Mass. 02154. Any size or speed. Send details to. Larry Kiner. W7FIZ. 7554 132nd Ave. N.E.. Kirkland, Wa. 98033. WE'VE BEEN RIPPED OFF! Dec. 11th in Madison, - Wisconsin. Collins. Model KWM.2, Transceiver, Ser- JOHNSON VALIANT - f 125.00, and SBE.33. $175.00. ial #I3551 with noose blanker. Waters filter. Both good, condition. W7ISJ. 8822 Driftwood, WDBNF modifications, and a Turner ceramic moke. Tucson, Arlz. 85715. Has many identifying features - I will be able to identify even if serial is removed. Call W9JS collect CANADIAN JUMBO SURPLUS and Parts Catalogs. at area code 312-665.0071, or report to the Madi- Bargains Galore. Send $1. ETCO-HR, Box 741, Mon- son Police Department. treal "A H3c 2V2.

TEFLON WIRE #22 gauge stranded, silver plated. WANTED: tubes, transistors, equipment, what have $1.75/100 ft. Rich Shyer. 625-4 S. Palomares, you? Bernard Goldstein, WZMNP. Box 257. Canal Pomona, Ca. 91766. - Station. New York. N. Y. 10013. QSL'S - BROWNIE W3CJl - 30358 Lehigh, Allen. town, Pa. 18103. Sampler with cut catalog 354. TELL YOUR FRIENDS about Ham Radio Magazine.

march 1974 83 L. I. Electronic Supermart (Off the wall self service) New P.C. Boards - G10, 1 oz. - 1 s~decopper. ftber glass 6" x 6". 80C ea. - 6 x 12, $1.50 ea. . 12 x 12. $2 85 ea. New P.C. Boards - 810, 1 oz. - 2 side copper- ftber glass 6" x 6". $1.10 ea. . 6 x 12. $2.00 ea. - 12 x THE ULTIMATE MORSE KEYBOARD 12, $3 75 ea. 0 I (II.I~.IItvr h~~ll,.r New P C Boards - GI0 Fiber glass puljch: St;incl.~rcltypr\vrit~r Ie~niint with spilcr F ~ait;rn 4 5 x 6.5. ,065 holes, 5 per 1 $1.30 P Pattern 4 5 x 6.5. .042 holes. 10 per 1" $1.35 (;,~mpat~hlewith KM-420 rnmmory G Pattern, 4.5 x 6 5. ,062 holes. $1.30 Availnhle 1 Nooembrr Model #KB-420C Pkg. 10 Btrcher P.C. Board. metal 2" sl~des $1.00 Write for specilicationr S499.95 Package of 50 fleaWWW.RADiOSCAMATORUL.Hi2.RO cltps for above punched Boards. ,062 75e 30 % or % W reststors, packaged 5 per value your cho~ce of values $1 00 251W reslstors, packaged 5 per value, your cho~ceof values $1 00 15-2W reslstors, packaged 5 per value, your cho~ce of values $1 00 5 1/1 or % W. 1% reststors. packaged 5 per value. your choice of values 50 5 ceramlc d~skcaps. .001-01. packaged 5 per value. your cho~ceof values .50 5 mtca d~pcaps, 1 pf.150 pf, packaged 5 per value. your cholce of values .50 5 mlca d~pcaps, 180 pf.820 pf, packaged 5 per value, your chotce of values .75 5 mtca d~pcaps, 910 f 1500 pf, packaged 5 per value, your cho~ceor values $ 1.00 Wlre Kit $22WWW.GiURUMELE.Hi2.RO solld PVC, 6 spools, 6 colors, 50' -WORLD QSL BUREAU1 ea. spool $3.50 THE ONLY OSL BUREAU to handle all Wtre Klt #? 22 stranded PVC. 6 spools. 6 colors, of your QSLs to anywhere: next door, the 50' ea. spool $3 5: W~reKit 324 Sol~dPVC, 6 spools. 6 colors. 50 next state, the next country, the whole ea. spool $3 50 world. Just bundle them up (please arrange W~reKit #24 stranded PVC. 6 spools. 6 colors. alphabetically) and send them to us with 50' ea spool $3 50 payment of 6c each. 10' - Ten cond. r~bbonwire. color coded. $22 5200 Panam8 Ave.. Richmond. CA USA 94804 or #24. stranded $1 50 C & K #7101 mlni switch. SPDT on-on $ 1.05 C & K ~7103mlnt sw~tch.SPOT on-off-on $1.20 C & K #7201 mlnl swltch, DPDT on-on $1.35 C & K $7203 mlni sw~tch.DPDT on-off-on $1.55 Alco 105D MST momentary on off-momentary on Radio Amateurs $ 1.25 Central Lab DPDT push momentary. SPEC. 4/$1.00 Connectors. PL259, f.45: PL258. J.70; 175U or 176U $ 20 ea UG 88 cu $ 50' UG 201 a/u (N td BNC adapter). 5.75: 'RCA 'to QHF. s 90 Encapsulated chokes luh to 5 Mh, choice 3/11 0: Varo type mlnl brldge rect~f~ers,approx. 5/~ -> . sq. size. 2 amp. - 50 v., $1.25. 4 amp. - 50 v.. $1.25; 6 amp. . 50 v. $1 25, 2 amp - 100 v.. WORLD PREFIX MAP - Full color. 40" x 28". shows $ 1.25: 4 amp. - 100 v.. $1 25: 6 amp. - 100 v.. P?P~!*CS I)!? rach country DX zones, tame zones. $1.25; 2 amp. . 200 v.. $1.50: 4 amp. - 200 v.. cllbes. cross referenced tables $1.25 $1.50: 6 amp. .. 200 v.. $1.50: 2 amp . 400 v., RADIO AMATEURS GREAT CIRCLE CHART OF THE $1.50: 4 amp .400v. $1.50: 6 amp. -400v.. $1.50 WORLD - from the center of the Untted States' Full - thermo tab package - 1 am 400 color. 30" x 25". lfstlnf! Great ClrCle bearings tn de v., s 80 ea.. 3 amp. - 400 v. $1.40 ea : f'akp - gr-es for stx major U S cltles. Boston. Wash~ngfon. 200 v. $1.20 ea. 6 amp . 200 v $1 40 ea' I> C. Mlarnl. Seattle. San Franc~sco& Los Angeles 6 amp. . 400 v., fi.60 ea : 6 amp - 500 v., $1 80 $1.25 ea : 8 amp . 200 v. $1 60 ea ; 8 amp . 500 v . 1 RADIO AMATEURS MAP OF NORTH AMERICA! Full $ 1.80 ea. 1 color. 30" x 25" - ~ncludesCentral Amer~caand tne To-5 case. 1 amp. - 200 v.. $ 70 ea.; 1 amp. - Caribbean to the eouator. showsne- call areas. zone 400 v.. $1.00 ea. boundar~es. prefnres and ttme zones. FCC frequency SCR 200 v. - 8 amp. thermo tab S.80 ea. chart, plus useful lnforrnatton On each of the 50 SEND SELF ADDRESSED ENVELOPE FOR Un~tedStates and other Counfrses $1.25 FREE MAILER. INCLUDES MANY HUNDREDS WORLD ATLAS - Only atlas cornp~ledfor rad~oama OF ITEMS NOT LISTED ABOVE. teurs Packed wlth world wlde lnformatton - tncludes Send check or money order include 6OC to I1 maps In 4 colors wlth zone koundar~esand coun - try prefixes on each map Also ~ncludes a polar pro cover parcel post and handltn UPS shtpping fectton map of the world plus a map of the Antarcltca avatlable. Mlnlmum order $4.58. - a cornplcte set of maps of the world 20 pages FREE BONUS WITH EACH $10.00 ORDER stze 8%" x 12" $2.50 50' SPOOL 600 V. #22 WC WIRE Complete reference library of maps - set of 4 as listed above $3.75 KRP See your favorite dealer or order direct. ELECTRONIC SUPERMART, INC. Mail orders ~leascinclude 50c ~erorder lor wstapc and Mndlnnq. I 219 WEST SUNRISE HIGHWAY FREEPORT, L. I., N. Y. 11520 516623-3346-9

84 match 1974 More Details? CHECK-OFF Page 94 QSLs CATALOG SAMPLES 3Se. Ritz Print Shop, 5810 Detroit Avenue. -Cleveland. Ohio 44102. GOOD NEWS - SRRC Hamfest June 2. 1974 at fabulous new site in Princeton Illinois Fairgrounds. SRRC-W;MKS. R.F.D. el. Box 171. Oglesby. Illi- nols 61348. - INCREASES THE REGENCY HR-2 OR HR-2A RADIOS TELETYPE MOOEL 19 with 14TD - $65.00: Sie- TRANSMIT CAPABILITY TO SIX ADDITIONAL FRE- mens ASR teleprinter (equal to 32 ASR) - $95.00; QUENCIES NO MAJOR CHANGE HAS TO BE MADE TO Model 28 stock ticker (strip printer) - $20.00: two THE RADIO WHEN INSTALLING THE 6T-HA2 DECK desk fay - both for $15.00. Plus shipping charges. Koppelmeier. 8025 Kolmar. Skok~e.Illinois 60076. MOBILE IGNITION SHIELDING provides more range with no noise. Available most engines in HF144U MOS FET PREAMP assembled or kit forms, plus many other suppros. s~onaccessories. Flee literature. Estes Engineering. OUR FAMOUS 2-METER PRE-AMP ST1 543.H West 184th. Gardena.- Californ~a 90248. IN THE HIGH BAN0 PRE-AMP FIELD BUY-SELL-TRADE. WriteWWW.RADiOSCAMATORUL.Hi2.RO for monthly mailer. give name, address, call letters. Complete stock of KIT $11.95 WIRED $17.95 ma'or brands new and recond~tioned equipment. Call us for best deals. We buy Collins. Drake. Swan etc. SSB & FM. Assoc~ated Radio. 8012 consir. Overland Park, Kansas 66204. 913.381-5901. SIGNAL ONE OWNERS. expert and prom t service with search back by ex.Signal/One engineer. Also will purcEase your function~ngor not functioning unit or spare parts. Write or call for deta~ls.Larry Pace. K21XP/7. 1071 IFICATION TO THE RADIO. GIVES USER A SC4NNING W. Roller Coaster, Tucson. AZ. 85704 (602-888-5234). TYPE R4DIO AT A FRACTION OF THE COST INCORPOR- ATES SEARCH BACK" A NEW AN0 EXCITING FEA- STEEL RELAY CABINET RACK. 76" high x 17" TURE TO SCANNING TYPE OPERATION. deep x 22" wide. Excellent condition. Has ground buss, outlet strip, switch box and screened WIRED ONLY back door for RFI. $100.00 or best offer. Must be picked up.WWW.GiURUMELE.Hi2.RO Harry Kundrat, 29 Walton Avenue, New Providence. New Jersey- 07974. (201) 665.1873. QSL's. Sample catalog 202. N & S Print. P. 0. Box 11184. Phoen~x. Ariz. 85061. NEW! Solid state speech rocessor kit. 26 dB + compression. $19.95 ppd. gpeech Products Co.. K. A. Teague. P. 0. Box 65.- Alma. Arkansas 72921. LEOS, sample pack of 10. includes green and yellow. $3.25 postpaid U.S.A. East Coast Electron. ICS. 50 Scott St., Hamburg.- N. Y. 14075. WANTED. APRIL 1970 issue of Ham Radio. Larry D. Van Duyn. K8JBL/5. 1802 Crescent Drive, Alamogordo. N. M. 88310. WE PAY HIGHEST 432 MHz TRANSMIlTER CONVERTER. 5 watts out. PRICES FOR ELECTRON 6939 mixer. 6939 amplifier and solid state LO chain. 4% x 71h cast aluminum box. Send for more information. Carm~chael Communications. TUBES AND SEMICDNDUCTORS P. 0. Box 256. Carrn~chael,- CA 95608. - PARTS BARGAINS: Motorola HEP 170 Epoxy Diode 2.5A/1000PIV 29c. 25.00/100: $15 copper antenna wire 1.95/C; 6x9 copper clad boards 69c; 3/16" H & L cable clamps 18c: Belden. Consolidated RG8 foam ASSOCIATES coax 17c/ft: CDE .001/10KV doorknob capacitor ELIZABETHPORT INDUSTRIAL PARK 1.95; Sigma l2VDC 4PDT/15A relay 3.95; Amidon toroid cores; RG63/U 15c/ft: RG22B/U 15r/ft: Mo- ELIZABETH. NEW JERSEY 072M torola sem~conductor data series 7.50; many old (201) 3514200 tubes. write needs. Monarch code oscillator module 1.50; Hammarlund variable HF50 PF 1.95; Sorensen .A ACR-2000VA AC regulator 150.00; Madison Elec- tronics. 1508 McKinney.- Houston. Texas 77002. ----- MOTOROLA PORTABLES - Expert repairs, reason- 1 able prlces, fast turmaround time. More details 65to 75% SAVINGS and flat rate catalog FREE. Ideal Services. 6663 lndustr~alLoop. Greendale.- Wi. 53127. I ELECTRONIC I FREE: 18 crystals of your choice with the purchase COMPONENTS of a new Genave GTX.200 at $269.95. Send cash- ier's check or money order for same.day shipment. I Rectifier D~odes and ieners Resistors (carbon, metal f~lrn,wire wound) Capaci. I For equally good deals on Drake. Swan. Standard. Clegg. Regency. Hallicrafters. Tempo. Kenwood. tors (molded electrolytic, dif~lm. tubular. Midland. Ten-Tec. Galaxy. HyGain. CushCraft, ceramic; electrolytic; tantalum; alumlnurn; Mosley. Sony, and Hustler, write to Hoosier E!ec- polyester: mylar; disc ceramlc: silver mica; tronics. your ham headquarters in the heart of specials) Memory Chips lC Sockets Fuses I I Pots Drllls for PC Boards Rubber Feet the Midwest. Become one of our many happy and . satisfled customers. Write or call todav for our low quote and try our ~ndiv~dual. servlce. FREE, NEW CATALOG Hoos~er Electron~cs, R. A. 25. Box 403. Terre Lists Many More at 25 to 75% Savings Haute. lnd~ana47802. (812)-894.2397. I I FTlOl LATE MOD x, w/CW filter, fan PRASAD ELECTRONICS - $30. D. Sachnoff. -----P. 0. Box 32, Addison. IL 60101 J

More Details? CHECK-OFF Page 94 march 1974 85 WESTERN N. Y. HAM FEST and only STA N DA R D VHF CONFERENCE Sells more STANDARDS MAY 17,18,1974 than Erickson ...and here's I whv! SRC-l46A Monroe County ERICKSON Fairgrounds SPECIAL Rt. 15A Wl TH WWW.RADiOSCAMATORUL.Hi2.RORochester, N. Y. Charger (Near Thruway Exit 46) "Stubby" antenna Leather case Ni-Cads Huge Flea Market 94/94,34/94 and one Top Programs channel of your choice Award Presentations $369 List --50 Pack- Discount Friday Night Cocktails $319 Prepaid - Cashiers Check or M.O. WWW.GiURUMELE.Hi2.ROERICKSON WNY HAMFEST COMMUNICATIONS ROCHESTER, N. Y. 3501 W. Jarvis Skokie, 111. 60076 (312) 677-2161

m E + ---isn*la

RTTY VIDEO DISPLAY UNIT

' ipEI ' ' 'I LELAND ASSOCIATES in0011 872$550 18704 GLASTONBURY RD DETROIT MI 48219 B-ARGAINS! I THE ULTRA-BAL 2000 1 KLEINSCHMIDT TELETYPE EQUIPMENT NOW-. -----An .xtr.melr ruggmd. *..tho.-prwf BALUN! I11 TT 100 PAGE PRINTER AS IS MI OR 100 WPM 159 95 .Full 2KW. 3 30 MHZ.. l:lorl:4rat+o.. ~AITT 117 PAGE Pn OR (8) TT 17s REPERF b TO AS IS 55995 .Sp.ci.l Tmflon insulation. Mar be used ABOVE CHECKED OUT OILED L ADJUSTED EA SR9 95 wilh tuned lines and 1un.r.. 12) TABLE $19 95 lC+ TABLE 534 95 lb) COPYHOLDER 53 95 .With dirole in.ulstor and h.np.up hod. (31 PAPERWINDER 514 95 (4) TT 107 REPERF. ONLY 54995 TH 5 CONVERTER TRANS/REC 100 CYCLES ADJUST TO 170 SHIFT 5.19 95 ONLY S 9.95ppd. I.1.t. ratio)

EXCLUSIVE 66 FOOT 75 THRU 10 METER DIPOLE

#I6 40% Copper Weld wire annealed so it handler like soft &per wire--Rated for better than full legal power AM/CW or SSB.Coaxial or Balanced 50 lo 75 ohm feed line-VSWR under 1.5 to 1 at most heights-Stainless Steel hardware- Drop Proof Insulators-Terr~fic PerformanctNo co~lsor traps to break down or change under weather cond~tions-Comp- letely Assembled ready to put up--Guaranteed 1 year-ONE DESIGN DOES IT ALL; 75-10HO-ONLY $12.00 A BAND! Model 75.10HD 560 00 66 Ft 75 Thru 10 Meters Model 75 40HD $40 00 66 Ft 75 Thru 40 Meters Model 75.20HD $50.00 66 Ft 75 Thru 20 Meters Model 40 20HD $33 00 35 Ft 40 Thru 20 Meters Model 80.40HD 542 00 69 Ft 80-40-15 Meter (CW) OR THRU YOUR FAVORITE ORDER DIRECT OR WRITE FOR 300H Shawnee DISTRIBUTOR FULL INF~RM*TION Leavenworth. Kansas 66048

86 5 march 1974 More Details? CHECK-OFF Page 94 DISCOUNT PRICES PLUS FULL WARRANTY, call or write for fast quote and delivery. All items new, guaranteed. 2M: Midland 13500 15W/12CH 219.95: SB144 193.95. Sp450TRC converts 2M-3/4M 149.00; Standard 826~~299.95; Ham-M 99.00: TR44 69.95; Belden &wire rotor cable 10~/ft;AR22R 31.95; CDE parts; 20% plus off Hygaln. Mosley: Hygain TH6DXX 143.00. TH3MK3 124.00 204BA 129.00: 402BA 144.00; dB10/15~96.00; ~'osleyClassic 33, CL36 MCQ3B Quad. MP33. Belden. Consolidated RG8 ioam coax 17~/it.Amphenol PL259 496'; Guar- anteed gear: Collins '75~1345,OO; 58303, filters (Mint) 350.00. Tentec 315 recelver 199.95. Cush. Craft ~147.22' 49.00 Dowkey llOVAC anteha re- lay 60 series 39,95.'~ohnson KW Matchbox 219.95; Triex W51 437.00.' MW50 283.00. MW65 374.00; MW35 175.00. write: Swan Tentec.'~rake. Kenwood, Electra ~eariat2-band scenner 129.95; 1972 Radio Masters 3.50; Callbooks; free flyer. Prices collect freight. Madison Electronics, 1508 McKinnev. Hous- ton. Texas 77002. 713/224.2668;WWW.RADiOSCAMATORUL.Hi2.RO Nite: 713/497-5683. MANUALS for most ham gear made 45/65, some earlier. Send SASE for specific quote. Hobby In. dustry, WaJJK, Box H.864, Council Bluffs, Iowa 51501. - LIGHTNING ARRESTORS. Joslyn DMA969 feed thru PREPARING rated 10 amps 9 kVp 2.32 MHz. $50.00 Vacuum capacitors: ~~'~1500.$150.00; MMC3000. $200.00; MMC 5000, $350.00. All unused. H. G. Husbands. 6626 Talrnadge. Dallas- 75230. PRINTED CIRCUIT DRILL BITS. Trumbull, 833 ,OR Balra Drive. El Cerrito, California 94530. OSCAR 7.? OUTBOARD FILTERS for Drake R4B. $75.00. Col. lins R-390A IF strip. $30.00. Drake W4 wattmeter, $40.00. H.WWW.GiURUMELE.Hi2.RO McDonald, 25617 Third St.. Barstow, California 92311. - HIGH-PERFORMANCE H.F. SYNTHESIZER replaces VFO and delivers output 1-30 MHz continuous coverage with accuracy, stability, resolution, and calibration to one Hertz. Write for information. Petit Logic Systems, Box- 51. Oak Harbor, Wa. 98277 TECH MANUALS for Govt. surplus gear. $6.50 each: R-220/URR R-274/FRR R-390/URR, URM-25D, URM.32. T+-~~A/FGC.TS:~~~D/U, USM-16, BC-779B, TS-497B/URR, LM-21. TS-34A/AP. PRC-10, GRR-5. ALR-5. TS-413A/U. ARR-7. GRC.19. TS-175/U. TS- 432 MHz J-BEAM 173/UR. Thousands more available., Send 50i. (coin) for list. W31HD. 7218 Roanne Dr~ve. Wash~ngton.- $47.50 D. C. 20021. - SEND PERFECT MORSE WlTH YOUR RTTY and save over $150 on price of a comparable Morse key- board. TMC-1 RTTY to Morse converter connects right into your loop trouble-free and accepts in- Rx MMc 144 put from keyboard or paper tape reader. Entire circuit including 64.1etter buffer memory on one 2-10 METER CONVERTER 4 x 6 inch board for $310. Write for information. Petit Logic Systems, Box- 51, Oak Harbor. Wa. 98277 $53.70 HAM RADIO. every issue. 1968 thru 1973. with two binders: first money order $65.00 postpaid; James W. Harrison. 1234 Little Bay Avenue, Norfolk, Va. 7?501 - 1000 PIV AT 2.5 AMP DIODES. New Motorola IMPROVE YOUR RECEPTION WlTH HEP-170. 10 for $2.50, 100 and up 206 each. post- oaid. K. E. Electronics. Box 1279. Tustin. Cali. iornia 92680. - KVG CRYSTAL FILTERS SELL: Drake R-4B RCVR and MS-4 SPKR $350; T-4XB XMTR and AC-4 power supply $450. Excel- XF9A SSB - 5 POLE $31.95 lent condition. Frans Liem-WBBEPJ. 5732 Rosebury XF9B SSB 8 POLE $45.45 Dr.. Dayton. Ohio 45424. Phone (513)-236.2050. - - XF9M CW - 4 POLE $34.25 RlTY BAUDOT LOOP TO ASCII CONVERTER accepts loop signal at any RTTY speed and del~vers cor- MATCHING OSCILLATOR CRYSTALS responding 6 or 8 level parallel ASCII, all on one 4 x 6 inch circuit board for $120. Petit Logic XF901 8998.5 kHz USE $3.80 Systems, Box 51. Oak Harbor. Wa. 98277 XF902 9001.5 kHz LSB $3.80 CAPACITORS WANTED: Computor-Grade, Tantalums, XF903 8999.0 kHz CW $3.80 Mylars. Discs. Write for top cash offer. National Electronic Supply, Dept. HI, 7231.8 Garden Grove F-05 CRYSTAL SOCKET 5O& Blvd., Garden Grove, Calif. 92641. (714) 893-2900 or (213) 597-7010. - SPECTRUM EMBROIDERED EMBLEMS AND PATCHES. Custom made from your design. 10 to 1000's. Write Rus. INTERNATIONAL sell. 1109 Turner St.. Auburn. Maine 04210. BOX 1084 CONCORD TRAVEL-PAK QSL KIT Converts photos, post cards to QSLs! Send call and 250 for ersonal sample. MASSACHUSElTS 01742 Samco. Box 203H, Wynantskill, Pf Y. 12198. si

More Details? CHECK-OFF Page 94 march 1974 87 Wilson Electronics Presents The Finest 2 Meter Handie Talkie With the Hottest Rx Front End on The Market. 2 METER FM TRANSCEIVER MODEL 1402SM FREQUENCY ...... 140 - 150 MHZ (2 MHZ SPREAD) , NUMBER OF CHANNELS ...... 6 Sirl)l,lieci with 146.94 Simplex 146.34/94 - 146.1 6176 WWW.RADiOSCAMATORUL.Hi2.ROR.F. Oirtpi~t...... 2 Watts rninimurn Sensitivity ...... letter than 0.3 MVl20 DB Q.S. Audio Output ...... 500 mv Meter ...... Monitors I~atteryvoltage -1 on Tx, S meter on Rx Weight ...... 1 Ib. 4 ounces without I~attieres WWW.GiURUMELE.Hi2.ROCurrent drain ...... 15 MA Rx 410 MA Tx Size 8 718" x 1 718" x 2 718" Includes Adjustable Whip Ant ,

00 Amateur Net Price MODEL 2 ACCESSORIES

1410A 12 Watt Power Amplifier i Also lr~cludesSteel Case For 1402SM - Charges 1402 SM When Plugetl Into C~garette Liohter 99.00 [- LCL LEATHER CAS 14BC BATTERY CHARGER ...29.95 SM1 SPEAKER MIKE ...... 24.00 WRITE FOR COMPLETE SPEC SHEETS. SEE YOUR NEAREST DEALER FOR THE FINEST AMATEUR HANDIE TALKIE ON THE MARKET DEALER INQUIRIES INVITED COMMERCIAL VERSION AVAILABLE 1410A W''. Wi/son Electronics P.O. Box 794 Henderson, Nevada 89015 Telephone (702) 451-5791 451-6650

88 fl march 1974 More Details? CHECK-OFF Page 94 WE BUY ELECTRON TUBES, diodes, transistors. integrated circuits. Semiconductors. Astral Elec- tronics. 150 Miller Street. Elizabeth, New Jersey World's Most Advanced 07207, (201) 354-2420.- WANTED - Technical manual for R.278B/GR rnili- STATE-OF-THE-ART tary receiver. WB5AY2, 1013 Indiana St., S.E., Al. buquerque, N. M. 87108.- TRANSCEIVER USED MYLAR TAPES - 1800 foot. Ten for $8.50 postpaid. Fremerman. 4041 Central. Kansas City. Mo. 64111. - SELL CHEAP: Eico e369 sweep.gen.. panel meters, vacuum-caps, I.C.'s. S.A.S.E. for listing. Samkofsky, 4803 Brenda Drive. Orlando.- Florlda 32806. VERY in-ter-est-ing! Next 5 big issues $1. "The Ham Trader. Sycamore ILWWW.RADiOSCAMATORUL.Hi2.RO- 60178 STANDARD 146-A (1.2) $238.70, (3.11) $212.30. Nicad batteries $1.58. Stubby antenna $5.00. Standard 826MA (1.2) $324.50. (3-11) $306.90. Standard 851T 25 watt mobile $420.20. Standard RTP.1 re. THE TRITON by TEN-TEC peater $600.00. HM-175 antenna $16.00. Base statton antenna HM.191 8.25 dB (list $169.50) net $119.95. Send check and we'll pay postage or we will ship COD. Electronics Communicat~ons Co., TOTAL SOLID STATE P. 0. Box 17222. Nashville. Tenn. 37217 (24 hr.) 6 15.8344999, - HF TRANSCEIVER CALCULATOR OWNERS: Use your -1-x.:. calcula. tor to compute square roots, cube roots, sin(X). cos(X), tan(X), arcsln(X), arccos(X). arctan(X), lo- garithms, .exponent~als, and more! Quickly. Accur. ately. Easily! Send today for the Improved and Ex. panded Edltion of the flrst and best calculator manual - now in use throughout the world . . only $2.00,WWW.GiURUMELE.Hi2.RO postpaid! Be sure to try this manuai before buylng a more expensive calculator - Ab. 1 Available ANYWHERE IN THE WORLDdirectly from solutely Unconditional Money.back Guarantee - and Fast service! Mallman Optics and Electronics Dept..H. 836 South 113. West Allis. Wiscons~n53214: ELECTRONIC DISTRIBUTORS, INC. - -Commun~catton Spec~al~stsfor over 35 years- QRP TRANSMATCH for the HW7 and other rigs. Wrlte Peter Meacham Associates. 19 Loretta Road. 1960 Peck St., Muskegon, Michigan 49441 Walthani. Mass. 02154.- Tel. (616) 726-3196 Telex 228411 DAYTON HAMVENTION expands to three days April 26. 27. 28. 1974 at HARA Arena and Exhi. b~tionCenter. Brochures mailed March 15th. Write for information if you have not attended the last two years. P. 0. Box -44. Dayton, Ohlo 45401. TEN TEC ARGONAUT with AC supply $190. Two.er $20. ARR-7. $25. 15/20/75 Hustler, $i0. HP-10. $30: Terry Welch, K41QT. 615.968.8152 weekdavs. TG-34A CODE KEYER 5.11 nn!,,,nt-:* .,,,$8-v.,.,.t - 1- TELETYPEWRITERS - Kleinschmidt - portable. r~r~f~r!~lies <,I '0 prnr tlic \ml:t>rl~s froin paper 1,7ne fixed, sets, punches, parts, recondltioned, reason. 5 to 1.1 WPM Ounlt ~n speaker Rrand new wtth tech able. Mark/Space Systems. 3563 Conqu~sta. Long manual. takeup reel and AC line cord Beach. Callf. 90808. 213.429.5821. $24.50 Code practsce tapes lor above P U.R DRAKE R4A. mint late model - $245 postpaid firm. Heath ~B30l'andSB401 combo In excelleni BC-1206-C RECEIVER Atrcraft Beacon ~e condition - $395 postpaid. f~rm.CW and AM fllters cctver 200 to 400 Kc Operates from 24V DC 1 5A included with SB301. Sam Leslie. W4EGY. 1307 E. Esther St.. Orlando. Fla. 32806. (305) 898-9413. Cont~nuoustunnng, vol control. on off swntch and - phone lack Very sensltlve Compact FIGHT TVI with the RSO Low Pass Filter. For bro- chure wrote: Taylor Communicat~onsManufacturing Complete wtth tubes. NEW $12.50 Compan Box 126. Agincourt. Ontarlo. Canada. MIS 3Bt - BC-603 FM RECEIVER REGENCY HR-ZA, 2m Xcvr. Serial no. 04.05632. Converted for 35 50 MHz 10 preset pushbutton Stolen from my home QTH 12 December 1973. JoAnne E. Moore. W8NSU. 112 Seward ~307, channels or manual lunnng Complete wlth Detro~t.Mich. 48202. 0 bechecked out I new $34.50 HOMEBREWERS: Stamp brings list of high quality AC Power Supply. New components. CPO Surplus. Box 189. Bra~ntree. DM 34 12V Power Supply. New f 445 Mass. 02184. - DM 36 24V Power Supply. Erc Used S 2 25 WANTED - TUBES 4-1000A 3.10002 3.4002 4. 400A. 4CX1000A. 4.'250~. 4.i25~. 81i, 811A. ' All Technncal Manual 1 2 50 letters answered. WB2PTI. Michael D. Harrison. Set of 10 tubes lor BC 603 Rece8ver 1 5 95 431 Windsor PI., Oceanside, L. I.. N. Y. 11572. (516) 536.5320. - BC-604 FM TRANSMITTER 20 to 27 9 MC HAM RADIO, complete run wanted; sell complete run. 73. KBJLK. Output appro-. 30 watts. 10 crystal controlled channels. Complete wllh tubes. FOR SALE: Drake 2NT xmtr. Heathkit VFO, one NEW $8.50 year old, perfect. $140 Write or call Richard Newman. 2 Clinton St.. ~ilford.connectidut 06460. 203.877-2205. - YOUR AD belongs here too. Commercial ads 35C per word. Non.commerclal ads 10c per word. Commercial advertisers write for special discounts for standing ads not changed each month.

More Details? CHECK-OFF Page 94 march 1974 89 New! Plugin modulator Depend on JAN Crystals. Our large stock of quartz crystal materials and components assures Fast Delivery from us. No modification or rewiring on your CRYSTAL SPECIALS Communicator. Just 2-METER FM for mosl Transceivers ea. $3.75 plug into mike jack 144-148 MHz - ,0025 TOl. and crystal socket. Frequency Standards Compact self-containedWWW.RADiOSCAMATORUL.Hi2.RO 100 KHz (HC 13lU) modulator measures 1000 KHz (HC 6/U) 4" x 3" ~1%". Almost all CB Sets. Tr. or Rec. (CB Synthesizer Crystal on request) Works w~thCommunicator I. 11. Ill, IV Any Amateur Band in FT-243 and GC-105. and other rigs listad. FM at a tenth the con of a new rig. For 1st class mail, add 20e per crystal. For Frequency adjust for netting built in. $34.50 postpaid U.S.A. $36.50 for PC-2, PC-62. HA-460. Spec~fytransmitter model. California res~dentsadd 5% sales tax. (HC-6/U crystal and 9 volt transistor battery not supp1ied.l WWW.GiURUMELE.Hi2.RO

WANTS TO BUY All types of rnllltary electronics equipment and CW FILTER parts. Call collect for cash offer. SPACE ELECTRONICS division of MILITARY ELECTRONICS CORP. 76 Brookside Drive, Upper Saddle River New Jersey 07458 (201) 327-7640 - ~.

New Mod., CWF-2BX->I8+ -5 Yd.1 CWF.2-112 'IS "I! *C 1 - -- ,$,,, I,, ,,%, r'8-a~. 8 ,,fw 114 '15 W.l,.l> 1(1%!...' illlll.lnlwd LOWER I, '0 lli yla"l. "#".,.C I, ,,il'..... ,.,,11.,0.. .0.1 1.10, Shsr. s.lrthilv Irom nnv rr.0v.r 0, tr.nsc.lr.. .E.,,.rn.l" hlph ,.,r, ,.,.rllon .Ora.I~c.ll~ Muc.. .It background nol.. .HO ."Oibl. no~l"~ Two models .No ,mp.d.nc. m.lrhlng --. . .U I,,. m0a.m ..,,". I,,,., d..,." us.. IC'. tor .up., htph P..lO,rn."C. w* nap,. *e ,hi". ,,n* I,nr p.. .,I >"1. %,,"., a*,: .Il".~".I. a" c,,nv, (>,<,, *,,, O*N s,r,r,, , m,,,; ,$ ,rt 1"" ,,b, "<. ,,,. , , -,... 1 ,, *, ,<.*,:*ah** I TIME .Ol,.,,n ..,., ,. .,,, III.....A."l arc, .... r. <,, $,** , ,.,r 28" a<,c, "'," ,,'

MC I $! A turn of knob and 2 color drum dlal shows t~meyour QTH and corresponding local t~me~n all zones . . . also GMT. Both models feature 2 color map panel of enamel on alumlnum 9" ~n length. MOOtl AMATEUR Nil MCI Unlfnlrhrd mahogany cabin?! Sq 90

ACI Pol~>htdacfyllc cabknrt Id 75 ,D* ,,,,. '*.,,.I..., C$..' !.., I* ">,,O,nIla". , r Il.C.,,..\1 , ,l.,"l.'..l.. ,\"I Add $1 25 lo! malltng COII ,-,.I.,. " ,,. .. ,,... :., , W'. * 8 '.*,'"', .el,.- . . .I<,.,...... 11.1. A .,. , ..* ,FA. A*..., "..

m,.,a ,"re mlrc". ..d -an ul m. an.r "I," I1I!*. .I It*. CW ".*I lilU I .I U.J 6605 Shoal Creek Blvd. to. -.. "1C C,, .d nb. -.. IUI*... Ad,. .*LII... 1 1 ..I*. C-,.l., c.11w.10. Austin. Texas 78757 MFJ ENTERPRISES L P 0 Box 494 A, Mnsa%appsStole MS 39762

90 march 1974 More Details? CHECK-OFF Page 94 -, I':F CALCULATOR IcAE1"Ro on~r '~ttractivel~designed! FxceIlent craf tsman- VARO FULL-WAVE BRIDCES ship. Case and keyboard (designed as one V5447 2A 400V $ .90 unit). Cabinet is made of high-impact V5647 2A 6OOV 1.10 plastic beige color with black bezel Xi810 Rect. 50V 1A .10 and amber window. Keyboard consists of a ?-position slide switch and 25 keys. 5 of which are used for mem- Special 811: Hex Inverter ory function. 20 keys gray, 5 keys TTL DIP Hex Inverter; pin interchangeable lorange. All keys mounted on one .- with SN 7404. Parts are brand new and are printed circuit board. This modu- branded Sirnetics and marked "811." lar unit is well suited far our ,t, EACH...... $ .30 Sheet 10 FOR... .. 2.50 L E Dls Supplied 100 FOR. ... 23.00 4 1000 FOR ... 220.00 MV50 red emitting S .25 10-4 ma @ 2V 5 FOR 1.00 0-9 plus RCA NUMITRON 4- letters. Gx-kz MAN 3M EACH $ 5.00 Right-hand decimal point...... MV5024 red TO-18 .75 WWW.RADiOSCAMATORUL.Hi2.RO121 $ Flat-pack type case. Long SPECIAL: 5 FOR $20.00 10 FOR b 50 operating life. IC "011 EACH $2.50 tage requirements. Ideal 10 OR MORE 1.90 for pocket calculators! WIO DECIMAL 1.50 S .30 10 FOR 2.50 MAN4 seven-segment. 0-9 plus let- This calcula- ters. Right-hand decimal point. Snaps in tor set pro- 14-pin DIP socket or Malex. IC voltage re- vides all of quirements. Ideal for desk or pocket calcu- the electronics SPECIAL 874 256-BIT RANDOM ACCESS MEMORY lators! far an 8-digit, TTL bi-polar fully-decoded 256 x EACH.. .$2.75 floating paint calculator with left- .... (~2 1 bit: TEN OR MORE 2.50 EACH hand entry. Keyboard. display, clock -- -"- generator, and display driver is all #Single 5V supply that need be added to make a calcula- n80 NS access time CD-2 Counter Kit tor that will add, subtract, multiply .Simple memory expansion thru This kit provides a highly sophisticated and divide. Overflow and negative 3-chip select lines display secrion module for clo~ks,~ounters. signals are also provided. Complete or other numerical display needs. The unit instructionsWWW.GiURUMELE.Hi2.RO to build a calculator Data with chip. 16-Pin DIP is .8" wide and 4 3/8" long. A single 5-volt $5.00 10 FOR $39.95 power source powers both the ICs and the '"'t:::$A, / '"'t:::$A, DATA...... $8.95 display tube. It can attain typical count DATA ONLY (Refundable).... 1.00 rates of up to 30 MHz and also has a lamp 3-Amp Power Silicon Rectifiers test, causing all 7 segments to light. Kit CT5005 CALCULATOR includes a 2-sided (with placed thru holes) This calculator chip has a full four- Marked Epoxy Axial Package fiberglass printed circuit board, a 7490, s function memory, which is controlled PRY PRICE PRV PRICE 7475. a 7147. a DR 2010 RCA Numi tron dlsplay by four keys. +n (adds entry into 100.. ...$ .10 800.. ...$ .I0 tube, complete instructions, and enough memory), 5 (subtracts entry from 200...... 15 lOOO.... .40 Molex pins for the ICs . . NOTE: boards can memory). CM (clear memory, without 400...... 18 1200.... .50 be supplied in a single panel of up to 10 clearing rest of registers). (read 600...... 23 1500 .... .65 digits (with all interconnects); therefore. memory or use as entry). when ordering, please specify whether you 12-Digit display and calcu- CMOS want them in single panels or in one multi- late ple digit board. Not specifying will result Fined decimal at 0, 1, 2, in shipping delay. 3, 4, or 5 COMPLETE KIT. Leading zero suppression ONLY $11.95 7-Segment multiplexed output FULLY-ASSEMBLED True credit sign display UNIT 513.00 Single 28-pin chip Boards can be supplied separately @ $2.00 CHIP AND DATA ...... ONLY $9.95 7400 Series DIP^ per digit. DATA ONLY (Refundable) ...... 1.00 5001 CALCULATOR LINEARS 40-Pin calculator chip will add, sub- Nf540 70-watt power driver amp...... $2.00 tract, multiply, and divide. 12-Digit NE555 precision timer...... 1.50 display and calculate. Chain calcula- NE560 phase lock loop DIP ...... 3.25 , - NE561 phase lock loop DIP ...... 3.25 I-----cions. True credit balance sign out- put. Automatic over-flaw indication. NE565 phase lock loop TO-5...... 3.25 Fixed decimal paint at 1, 2, 3. or 4. NE566 function generatar TO-5 ...... 4.00 NE567 tone decoder.. 4.00 Leading zero suppression. Complete ...... NE5558 dual 741 op amp MINI DIP. 1.00 data supplied with chip...... CHIP AND DATA ...... ONLY $9.95 709 popular op amp DIP...... 45 DATA ONLY (Refundable). 1.00 110 voltage comparator DIP ...... 75 ... 711 dual comparator DIP...... 40 A11 ICS are new and fully-tested; 74L10 .35 74H74 .80 723 precision voltage regulator DIP. 1.00 leads are plated with gold or solder. 74Hll .35 7475 1.40 741 op amp TO-SIMINI DIP ...... 55 Orders for $5 or mare will be shipped 7413 1.25 7476 .60 747 dual 741 op amp DIP...... 1.00 prepaid. Add 35C for handling and 7417 .40 74L78 .80 748 op amp TO-5 ...... 1.00 postage for smaller orders; residents 7420 .25 7480 .65 CA3018 2 isolated transistors and a Dar- of California add sales tan. IC or- 74L20 .35 7483 1.00 lington-connected transistorpair 1.00 ders are shipped within 2 ~orkdays-- 74H20 .35 7489 4.00 CA3045 5 NPN transistor array ...... 1.00 kits are shipped within 10 days of 74822 .35 7490 1.20 CA3026 dual differential amp...... 1.00 receipt af order. $10.00 minimum on 7430 .25 7491 1.00 LM~OO positive DC regulator TO-5...... 1.00 C.0.D.s (phone in). 74830 .35 7492 .90 ~nlO5 voltage regulator ...... 1.25 --HAIL ORDERS: -- 74L30 .40 7493 1.15 LM302 op amp voltage follover TO-5.... 1.25 P. 0. Box J 4811 nyrtle Ave. 7440 .25 7494 1.15 LU307 op amp...... 50 Carmichael, CA Sacramento, CA 7hH40 .35 7495 1.15 LM308 op amp To- ...... 2.00 I3311 comparator TU--5 1.75 95608 (916) )j&.2161 7441 1.25 74L95 2.00 ...... 7442 1.20 74121 1.25 m370 AGC amplifier ...... 2.00 EOEEX gdcKKGgA.y~EEIo~6Lk g.7gDz: m703 RF-IF amp epoxy TO-5...... 45 SEND FOR FREE FLYER LISTING looas OF m309K 5v-1A power supplv nodule TO-3.. 2.00 MONEY -SAVING BARGAINS ! ::%$ ;:;:a k::: 7448 1.00 74161 2.00 I33900 quad op amp ...... 2.00 7450 .25 74163 2.00 ~M15954-quadrant multiplier ...... 2.00 RRRYLOn 74850 .35 74193 1.50 8038 sine square triangle function .25 74195 1.00 generator ...... 4.95

More Details? CHECK-OFF Page 94 march 1974 a 91 intelligences. Stable and accurate enough to use as freq. meter! Net wt. 276 Ibs. in 2 cabinet in rack cradle 750.00

WWVB 1 KHz tones, use to calib. 100 KHz ...... 175.00 38-1000 MHz by Band Switching, 4 bands: Separate an- tenna for each band. AN/ALR.5 modlfied for 117 v 50/60 cy line. AM/FM. The Tuner is a plug-in Converter. the receiver is 30 MHz IF and all that follows IF. dhoose selectivities 200 KHz or 2 Mtiz each side of center. Fac- MODEL "A" Frequency Counter Price 1299.00 tory checkout sheet, typical for the original-pack tuner lOHz to 80 MHz (2 1Hz) Direct Count guar. you get, says sensitivityWWW.RADiOSCAMATORUL.Hi2.RO ranges from 1.lrV at 28 MHz to anteed (1Hz to over 100MHz) typical) 7 at 1 gHz. IF attenuator IS calibrated in 6 dB steps to Read Out: 5 LED digits 1- LED Over Range -74 dB. Diode current meler makes this rcvr useful for Sensit~vity: Less than 100 millivolts over en- relative field strength measurements and harmonic f~ndcr. tire range. Rcvr unil is exc. used and checked out OK . 375.00 Power Req.: Either 120 VAC or 12 VDC 15 watts approx. 30 MHz PANADAPTER may be useful with above . . 295.00 Small Sue: 2.34" x 5.68" x 8.18" A.I.L. #I32 30 MHz rcvr/amplifier/atlen. calib. . 49.50 Overload protected input and DC Dower input. EDDYSTONE AM/CW/FM/NBFM 19-165 MHz rcvr . . 295.00 MODEL "AS;' ~requency'Counter price $375.00 Exactly as above plus an internal 250MHz CV-591A: SSB Converter either sideband ...... 137.50 Scaler (rklOHz to well over the guaranteed frequency of 250 MHz.) No external power is required. snlftlng DECIMAL POINT gives a DIRECT Attention1 I READOUT of VHF Freauencies. I One BNC INPUT for both ranges. No cable changlng from HF to VHF. WWW.GiURUMELE.Hi2.ROI (CA residents add State Sales Tax) I I Dealer inquiries invited I

P.O. BOX 1672 ~~A1~~9~~~3s

NEW -440 MHz PREAMPS I

s54-95POSTPAID puy I

Two stage preamps use KMC Elpolar and Mos- fet Transistors. 20db gain. 20 MHz bandwidth. These are high quality preamps sultable for the I most demanding applications. AC models have I die cast case, oihers have metal enclosure. 432PA 3.5db NF l2VDC $29.95 432PA-1 3.5db NF 117VAC $54.95 432PC 1.5 to 2.0db NF l2VDC $69.95 432PC-1 1.5 to 2.0db NF 117VAC $94.95

P. 0. BOX 112 JANE SUCCASUNNA, N. J. 07876 LABORATORIES 201-584-6521

BROADBAND AMPLIFIERS, for amateur, MATV, CATV and commercial use We offer a quality line of low noise. Depending upon model. gain to 50dB. low IMD amplifiers covering the re- flatness to :+. 1 dB and Noise Figure gion from 2 MHz to 1.5 gHz. For less than 3 dB may be selected. Op. communication use. simple filters at eration is from 12 to 15 volts d-c the input will yield coverage of the or 115 volts a-c. PIN diode protec. bands of your choice. Where remote tion for incident power to 25 watts location is necessary to offset line is available. Prices vary from $30 losses. coax powered versions are to $130 depending upon model and available with adapters or power options. Warranty is for one year on supplies. all parts and labor. 11 RADIATION DEVICES CO., P. 0. Box 8450, Baltimore, Md. 21234 11 Pleaw write for information on our other products including RF Multimeters. VSWR Bridges, Detectors, L-C. Crystal and Tunable Activo Peak-N-Notch Filters.

92 march 1974 More Details? CHECK-OFF Page 94 10-DIGIT DESK CALCULATOR WITH DIGITALWWW.RADiOSCAMATORUL.Hi2.ROCLOCK AND

/ In clock position, hours, minutes and seconds are displayed in alter-

/ Automatic day update, automatic WWW.GiURUMELE.Hi2.ROmonth update.

now famous single-chip calculator inte-

speed entries. lator industry allowing noiseless, corn- pact design and portable operations. / One year full warranty. TUCKER says - try the 305 for 30 days - if you don't agree it's the best, return it for full credit.

Mail to: TUCKER ELECTRONICS CO., P.O. Box 1050, Garland, TX 75040 or CALL TOLL FREE 800-527-4642 (in Texas call 214-348-8800)

Please send me- 305 Calculators at $99.95 each plus $2.76 for shipping and handling. (Residents of California, Illinois, New Jersey and Texas add 5% tax.)

0 Bill my Master Charge 0 BankAmericard O American Express

Card No. Name -

Expiration Date Address - .- - -- -~---- -

Signature--.- -.

Check Enclosed ------.. -

Ship COD City/State .__ Zip- ~ -

More Details? CHECK-OFF Page 94 march 1974 93 Ad~erTisers check-offv'

WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

House of Dlpo

lnternat~onalElectronlcs Unl~mtted Jan Crystals 90 Janel Labs 92 Jeff Tronlcs 80 K E Electron~cs 86 KLM Electrontcs 70 KRP Electron~cSupermart Inc 84 Larsen Electron~cs 59 Leland Assoc~ates 86 L~nearSystems. Inc 72 Loglc Newslette 74 MFJ Enter~rlses 90

Raytheon Company 5 Regency Electrontcs. Inc 60. 61 Rochester Hamfest 86 Limit 15 inquiries pet request. Savoy Electron~cs Cover II Space M~lttary Electron~cs 90 Specialty Products 80 March 1974 Spectronlcs. FM 53 Please use before April 30, 1974 Spectrum lnternat~onal 87 Star Tron~cs 70 Tear off and mail to Swan Electron~cs 21 Ten.Tec. Inc HAM RADIO MAGAZINE - "check off" Topeka FM Cornmun~cattons& Greenville. N. H. 03048 Trt Ex Tower Corp Trl Tek Inc Tnstao Tower Co NAME...... Tucker Electron~cq .... U J lndustr~es VHF Englneer~ng.Dlv of CALL BrownIan Elect Corp Venus Sc~ent~f~c STREET...... We~nschenker. M W~lson Electronlcs Wolf S CITY ...... World QSL Bureau Y & C Electrontcs STATE...... ZIP...... Yaesu Musen USA

94 march 1974 WWW.RADiOSCAMATORUL.Hi2.RO

WWW.GiURUMELE.Hi2.RO

The TRITON is a One-of-a-Kind HF transceiver, totally solid state including the final amplifier. The new generation that does more things better than ever before. One, you can change bands instantly. Just turn the band switch-and go! Two, there is less internal heat to prematurely age components and no high voltage to break down insulation or cause accidental shock. Three, it has ample reserve power to run at full rating even for RTTY or SSTV without limit. Great for contests or emergency service. Four, it is light and compact with a detachable AC power supply to work directly from 12 VDC-For mobile operation without tedious installation. Five, the TRITON is a delight to operate. SSB is clean, crisp and articulate. Amplified ALC puts all available speech power into the antenna without splatter. CW is wave-shaped to cut through QRM and pile-ups. Instant break-in (not "semi" which really isn't break-in) lets you monitor the frequency while transmitting. And six, a lot more goodies such as excellent dial illumination, plug-in circuit boards, offset tuning, built-in SWR bridge, speaker, crystal calibrator, snap-up anti-parallelax front feet, light indicators for offset and ALC, direct frequency readout, WWV. entire 10 meter band coverage-and a lot more. The TRITON brings together all that is new and exciting in Solid State for your greater enjoyment of Amateur Radio.

We'll be happy to send you full Informallon. TRITON 1 100 watts input...... Sl9.00 TRITON 11 200 wans input...... 606.00 Model 251 Supply for TRITON 1...... 69.00 TEN-TEC, IMC. Model 252 Supply for TRITON if.... 89.00 SEVIERVILLE, TENNESSEE 37662

1 More Details? CHECK-OFF Page 94 march 1974 95 Miscellaneous from Barry NPC POWER SUPPLIES 115 VAC lnput . 12 VDC 4 $24.95 Same as above but regulat $34.95 115 VAC lnput - 12 VDC 10 $54.95 Ham-M Rotators C.D. TR.44 Rotators new. complete. $69.95 Cable for Ham-M & TR.44 14c/ft. Coll~ns 152-J1 Phone Patch $24.95 Er~efeed thru ceramtc capacitors, 1500 pf with hard. ware 70c Vlctoreen Radiological Survey Meter with 20 uA meter. Or~glnalbox, unused $19 95

TMC RF Master Oscillator. 2.64 Mcs on harmontcs. WWW.RADiOSCAMATORUL.Hi2.ROrelay rack mount excellent, $150.00

DUMMY LOAD, WATTMETER, ONE KW inventory of Eimac tubes, ch~rnneys, sockets.

fMfrom Barry Clegg FM-270. 146-148 MC coverage with- out buylng a crystal. Fully synthesized IC.22 22 channel. 2 meter transcetver. Very hot re. celver. 10 WWW.GiURUMELE.Hi2.ROwatts out $289.00

Completely synthesized with Tempo TPL 1002.3. 2.meter amplifier. 10 watts in. 130 phase locked loop. watts out $ 220.00 Slngle Knob Control, Drake TR.72. 2-meter FM transce~ver, 23 channels. Smart compact styl~ng 1 or 10 watts output. 13.8 volts $320 00 GE Model YGS-3 FM s~gnalgen. 1.150 Mc. excellent. no manual $200 00 SEE-450 TRC Transverter. 2 meters In. 450 Mcs out $ 179.95 See Barry for Receivers Harnmarlund HQ-180 with SSB $225.00 Slow Scan Monitor Hall~craftersSX.100 wlth SSB $100.00 Halllcrafters SX-I10 gen. coverage $99.95 Heath SB.301 wlth SB-620 Scanalyser and 58-600 Speaker Wr~te Nat~onal NC-88 General Coverage w~thband spread VENUS C1 for ham bands. 80 meter band needs repalr fa~rlygood. $55.00 Motorola R-220 20.220 MCS. All Modes: Write Fast ScanlSlow Scan Camera & Converter HF Gear from Barry M~croBarfocus Generator. I/. ~nch Reversalto ~nf~n~ty Hallicrafters FPM-300 Safar~. 5 bands 80-10 meters Shlpplng Prepa~d net $625.00 A Free Hustler 4BTV Vertical Antenna w~thevery FPM 300 regular prlce $49.95 Barry Now Stocks Bogen. Electrovolce & Unl. - vers~ty.Call or Wr~te. Famous Trtton.11 by Ten.Tec. Fully sol~d-state. 200 0 watt transcelver. 5 bands . full break In on CW $606.00 CASH PAID . . FAST1 For your unused Ten.Tec 252 AC Power Supply $89 00 TUBES, ~em~conductors.RECEIVERS. VAC. Ten-Tec Model 315 Rece~ver $229 00 VARIABLES. Test Equ~pment. ETC. Wrlte or CW F~lter $14.95 call Now' Barry. WZLNl We Buy1 We shlp Drake TR.4C Transce~ver new, $599 95 all over the World Thousands of unadver. AC.4 Power Supply $99 95 t~sedspec~als. F 0.0. polnt of sh~pment. Drake R4-B Super Mint, Extra Crystals Wrlte Coll~ns30L-1 L~nearAmpl~f~er ood, 5375.00 0 Send for Green Sheet Supplement 23. Colllns 3128-4 Statlon Control ood. $149.00 Send 50c postage & handl~ng(refund 1st Coll~ns3128.5 Stat~onContro Wr~te order).

BA R R Y 512 Broadway NY, NY 10012 DEPT. H-3 212 - WA-5-7000 ELECTRONICS TELEX 12-7670

96 march 1974 More Details? CHECK-OFF Page 94 WMEM YOU BUY KEMWOBD

PRIDE, PLEASURE & PERFORMANCE Pride in knowing that you own today's ultimate in state-of-the-arttech- nology. . .pleasure in operating a rig whose day in, day out performance will show you why theWWW.RADiOSCAMATORUL.Hi2.RO Kenwood name is world-famous for reliability and value.

i: .... .- Kenwood's superb qp.'-:e1-. . state-of-the-art SSB transceiver -... -- ' -.- a.1 - -- .m,rcm- -.- WWW.GiURUMELE.Hi2.RO mL ..the ultimate transceiver. The promise of the -too numerous to list. Its specifications are superb. ransidor hm bean fulfilled. Here is the transceiver The TS-900 is unquestionably the best transceiver ,ou will want to own .. . whatever you have now, of its kind ever offered. The price . . . . $795.00 et ready to trade up. Its important features an, far PS-900 (AC Supply) $120.00. the DS-900 $140.00 Kenwood's go every place TS-528 . . . do everything transceiver The new TS-520 is the transceiver you have wanted, but could not buy until now. It is a noncompromise, do everything, go everywhere 5 band transceiver for SSB or CW that performs equally well at home, in an automobile, airplane, boat or trailer. The TS-520 features built-in AC power supply, built-in 12 volt DC power supply, built-in VOX with adjustable gain delay and anti-VOX. The price ...... $599.00 - n -- , The R-599A is the most high voltaged, CW-LSB- complete receiver ewr of- USE-AM opmtion. fered. It is solid state. The mice .$459.00 n . . . superbly reliable, small and lightweight, coven . the full amateur band . .. 10 thru 160 meters. CW, LSB. USB, AM, AM.N and FM. The price . . . .$439.00 7 The T-599A is mod" solid state.. . only 3 tubes, has built-in power *-.-- supply, full metering - (ALC. Ip, RF output & - ?.FiF198. -- .,. . .Rpepiwr.---. - -. T-599A Transmitter Please call or write for Complete SDeciflcations. Also available at Kenwood dealers throughout the U.S. The DX Champion.

In contest after contest, contact after contact, you'll hear the EIMAC-equipped stations come out on top. Join the elite operators who choose EIMAC WWW.RADiOSCAMATORUL.Hi2.ROfor power, dependability and quality. You'll be in good company.

For technical information on EIMAC products, contact the EIMAC Division of Varian, 30 1 Industrial Way, San Carlos, California 94070. Or any of &2J the more than 30 Varian/EIMAC Elec- tron Tube and Device Group Sales ~IVI~IO~ Offices throughout the world. varlan WWW.GiURUMELE.Hi2.RO